Trial Outcomes & Findings for "Facemask Use During High-intensity Interval Exercise in Temperate and Hot Environments" (NCT NCT05143801)

NCT ID: NCT05143801

Last Updated: 2022-04-25

Results Overview

Heart rate measured in beats per minute using a cardiograph impedance device (PhysioFlow)

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 10 participants
• Primary outcome timeframe: During a 20-minute high-intensity interval exercise session
• Results posted on: 2022-04-25

Participant Flow

Participants were excluded if in the last 6 months they smoked, performed less than 150 minutes of moderate-intensity exercise per week as defined by the American College of Sports Medicine guidelines, had a cardiorespiratory fitness classification below the 50th percentile for age and sex according to the American College Sport Medicine guidelines, reported no experience performing high intensity interval exercise, or had any known medical disease.

Participant milestones

Measure	All Participants Ten recreationally trained participants (5 males; 5 females) were recruited for this study. A randomized non-counterbalanced crossover repeated measures design was used to compare cardiovascular, thermoregulatory, metabolic, and perceived responses before and during high intensity interval exercise across four experimental trials performed during two visits with each visit lasting approximately 4 hours. For each high intensity interval exercise visit, which was separated by a minimum of 72 hours, the participants completed two high intensity interval exercise sessions separated by 3 hours of rest. The high intensity interval exercise sessions were performed in a temperate environment with and without a surgical mask, and in a hot environment with and without a surgical mask. During the 3-hour rest period participants were provided a 350-calorie meal (7 grams of Fat; 64 grams Carbohydrate; 9 grams of Protein) and water ad libitum.
Overall Study STARTED	10
Overall Study COMPLETED	10
Overall Study NOT COMPLETED	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Measure	Participation in Four Different Conditions n=10 Participants Ten recreationally trained participants (5 males; 5 females) were recruited for this study. Participants were free from known cardiovascular, renal, metabolic, or chronic respiratory disease (i.e., asthma) as determined from a health history questionnaire. Participants were excluded if in the last 6 months they smoked and performed less than 150 minutes of moderate-intensity exercise per week, had a maximal oxygen consumption capacity below the 50th percentile for age and sex according to the American College of Sport Medicine guidelines for aerobic fitness, or reported no experience performing high intensity interval exercise. A pregnancy test was completed for female participants to include only non-pregnant participants. A randomized non-counterbalanced crossover repeated measures design was used to compare cardiovascular, thermoregulatory, metabolic, and perceived responses before and during high intensity across four experimental trials performed during two visits. The high intensity interval exercise sessions were performed in a temperate environment (23°C, 25% relative humidity) with and without a surgical mask, and in a hot environment (36°C, 14% relative humidity) with and without a surgical mask.
Age, Continuous	27.8 years STANDARD_DEVIATION 4.8 • n=10 Participants
Sex: Female, Male Female	5 Participants n=10 Participants
Sex: Female, Male Male	5 Participants n=10 Participants
Height (cm)	173.1 centimeters STANDARD_DEVIATION 7.5 • n=10 Participants
Weight (kg)	68.6 kilograms STANDARD_DEVIATION 11.5 • n=10 Participants
Resting SBP (mmHg)	113.0 millimeters mercury STANDARD_DEVIATION 8.0 • n=10 Participants
Resting DBP (mmHg)	75.4 millimeters mercury STANDARD_DEVIATION 5.9 • n=10 Participants
Resting HR (bpm)	64 beats per minute STANDARD_DEVIATION 9 • n=10 Participants
VO2max (mlO2/kg/min)	49.4 mlO2/kg/min STANDARD_DEVIATION 7.4 • n=10 Participants
Max Power (Watts)	284.0 Watts STANDARD_DEVIATION 78.0 • n=10 Participants

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

Heart rate measured in beats per minute using a cardiograph impedance device (PhysioFlow)

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Heart Rate Over the Course of High-intensity Interval Exercise	144 beats per minute Standard Deviation 21	143 beats per minute Standard Deviation 20	148 beats per minute Standard Deviation 18	149 beats per minute Standard Deviation 18

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

Stroke volume measured in milliliters using a cardiograph impedance device (PhysioFlow)

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Stroke Volume Over the Course of High-intensity Interval Exercise	109.9 milliliters Standard Deviation 19.5	109.2 milliliters Standard Deviation 15.3	104.5 milliliters Standard Deviation 16	101.5 milliliters Standard Deviation 36.4

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

Cardiac output measured in liters per minute using a cardiograph impedance device (PhysioFlow)

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Cardiac Output Over the Course of High-intensity Interval Exercise	15.7 L/min Standard Deviation 2.5	15.8 L/min Standard Deviation 2.6	15.3 L/min Standard Deviation 2.4	16.5 L/min Standard Deviation 2.2

PRIMARY outcome

Timeframe: The highest value recorded during a 20-minute high-intensity interval exercise session

The highest core body temperature measured in degrees Celsius during high-intensity interval exercise

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Peak Core Temperature	37.76 °C Standard Deviation 0.28	37.64 °C Standard Deviation 0.29	37.65 °C Standard Deviation 0.24	37.71 °C Standard Deviation 0.38

PRIMARY outcome

Timeframe: Baseline (rest) prior to exercise and immediately after 20-minutes of exercise

The difference in core temperature from rest prior to exercise and at the end of exercise

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Change From Baseline (Rest) in Core Temperature to the End of Exercise	0.77 °C Standard Deviation 0.22	0.54 °C Standard Deviation 0.26	0.56 °C Standard Deviation 0.20	0.64 °C Standard Deviation 0.17

PRIMARY outcome

Timeframe: Change from Baseline (rest) prior to exercise and after 20-minutes of exercise

Amount of fluid loss through sweat over the course of exercise reported in milliliters per hour. This was calculated by taking difference of pre- and post-exercise body weight in kilograms while accounting for fluid intake and urine volume.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Sweat Rate During Exercise	2097 milliliters per hour Standard Deviation 1258	1921 milliliters per hour Standard Deviation 690	2262 milliliters per hour Standard Deviation 1199	1793 milliliters per hour Standard Deviation 1254

PRIMARY outcome

Timeframe: Change from baseline at rest and after 20-minutes of exercise

Percentage of body weight fluid loss represented as a percentage of change from baseline and after 20 minutes of exercise

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Dehydration After Exercise	-0.76 percentage of change Standard Deviation 0.32	-0.77 percentage of change Standard Deviation 0.26	-0.81 percentage of change Standard Deviation 0.25	-0.67 percentage of change Standard Deviation 0.28

PRIMARY outcome

Timeframe: 5-minutes post exercise

Blood lactate measured in millimoles per liter. This measurement was taken at the earlobe using a sterile lancet to obtain a drop of blood for analysis.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Lactate at 5-minutes Post Exercise	4.3 mmol/L Standard Deviation 1.7	4.2 mmol/L Standard Deviation 2.0	4.9 mmol/L Standard Deviation 2.2	4.5 mmol/L Standard Deviation 1.9

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

A pulse oximeter was placed on a finger and used to measure the percentage of oxygen saturated blood.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Blood Oxygen Saturation Over the Course of High-intensity Interval Exercise	93.5 percent SpO2 Standard Deviation 3.63	93.7 percent SpO2 Standard Deviation 1.5	93.8 percent SpO2 Standard Deviation 2.3	94.0 percent SpO2 Standard Deviation 1.4

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

A near-infra red spectroscopy device was placed over the vastus lateralis of the dominant leg. This device measured the percentage of oxygenated muscle tissue.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Muscle Tissue Oxygenation During the High-intensity Portions of the Exercise Session	31.0 percent SmO2 Standard Deviation 17.8	31.4 percent SmO2 Standard Deviation 21.5	23.5 percent SmO2 Standard Deviation 18.8	34.7 percent SmO2 Standard Deviation 21.7

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

A near-infra red spectroscopy device was placed over the vastus lateralis of the dominant leg. This device measured the percentage of oxygenated muscle tissue.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Muscle Tissue Oxygenation During the Active Rest Portions of the Exercise Session	56.7 percent SmO2 Standard Deviation 10.4	58.8 percent SmO2 Standard Deviation 15.9	55.8 percent SmO2 Standard Deviation 12.7	62.0 percent SmO2 Standard Deviation 11.4

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

This value was calculated by subtracting the average percentage of muscle tissue oxygenation during active rest portion of the exercise from the average percentage of muscle tissue oxygenation during the high-intensity portion of the exercise.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Change in Muscle Tissue Oxygenation Between the Active Rest and High Intensity Portions Over the Course of High-intensity Interval Exercise.	25.6 percent SmO2 Standard Deviation 10	27.5 percent SmO2 Standard Deviation 10.2	32.4 percent SmO2 Standard Deviation 12.4	27.4 percent SmO2 Standard Deviation 13.7

PRIMARY outcome

Timeframe: Measurements were taken prior to, 10 minutes into exercise, and immediately after exercise (at 20 minutes). These measurements were averaged to form a single value for the high-intensity interval exercise session.

The participants were presented a vertical 200 millimeter long line with the top of the line labeled "No Difficulty" and the bottom of the line labeled "Most Difficult". The participants were then asked to indicated on this line how difficult it was to breath by pointing to a point along the line presented to them. Once the participant indicated along the line how difficult it was to breath the researcher then marked the spot on the line with a pen. To quantify the measurement, the distance, measured in millimeters, was taken from the "No Difficulty" end of the line (0 millimeters) to the indicated mark with the maximum difficulty recorded as 200 millimeters.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Perceived Dyspnea Score Over the Course of High-intensity Interval Exercise	14 units on a scale Standard Deviation 13	44 units on a scale Standard Deviation 17	18 units on a scale Standard Deviation 15	58 units on a scale Standard Deviation 22

PRIMARY outcome

Timeframe: Baseline (rest) and every four minutes that was assessed up to 20 minutes into exercise. The highest value was recorded for each exercise session.

Participants were asked to indicate on a visual scale from 0 (very cold) to 8 (very hot) their perceived thermal sensation. The highest recorded value was reported.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Peak Thermal Sensation Over the Course of High-intensity Interval Exercise	5.9 score on a scale Standard Deviation 0.9	5.9 score on a scale Standard Deviation 0.9	6.5 score on a scale Standard Deviation 0.4	6.6 score on a scale Standard Deviation 0.4

PRIMARY outcome

Timeframe: Baseline (rest) and every four minutes that was assessed up to 20 minutes into exercise. These values were averaged into one value for each exercise session.

Participants were asked to indicate on a visual scale from 0 (very cold) to 8 (very hot) their perceived thermal sensation.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Average Thermal Sensation Over the Course of High-intensity Interval Exercise	5.3 score on a scale Standard Deviation 0.7	5.4 score on a scale Standard Deviation 0.7	6.5 score on a scale Standard Deviation 0.4	6.6 score on a scale Standard Deviation 0.4

PRIMARY outcome

Timeframe: Baseline (rest) and every four minutes that was assessed up to 20 minutes into exercise. The highest value was recorded for each exercise session.

Participants were asked to indicate on a visual scale from 6 (no exertion) to 20 (maximal exertion) their perceived difficulty of exercise. The highest recorded value was reported.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Peak Rating of Perceived Exertion Over the Course of High-intensity Interval Exercise	15 score on a scale Standard Deviation 2	15 score on a scale Standard Deviation 1	15 score on a scale Standard Deviation 2	16 score on a scale Standard Deviation 2

PRIMARY outcome

Timeframe: Baseline (rest) and every four minutes that assessed up to 20 minutes into exercise. These values were averaged into one value for each exercise session.

Participants were asked to indicate on a visual scale from 6 (no exertion) to 20 (maximal exertion) their perceived difficulty of exercise. The highest recorded value was reported.

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Averaged Rating of Perceived Exertion Over the Course of High-intensity Interval Exercise	13.3 score on a scale Standard Deviation 1.4	13.3 score on a scale Standard Deviation 1.2	13.5 score on a scale Standard Deviation 1.2	14.3 score on a scale Standard Deviation 1.3

PRIMARY outcome

Timeframe: During a 20-minute high-intensity interval exercise session

Peak heart rate measured in beats per minute using a cardiograph impedance device (PhysioFlow)

Outcome measures

Measure	No Mask Temperate n=10 Participants Participant exercised in room temperature environment not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition without wearing a surgical face mask	Mask Temperate n=10 Participants Participant exercised in room temperature environment while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a temperate environment: Participants performed high-intensity interval exercise in a temperate environmental condition while wearing surgical face mask	No Mask Hot n=10 Participants Participant exercised in a hot environmental temperature not wearing a surgical face mask High-intensity interval exercise without using a surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition without wearing a surgical face mask	Mask Hot n=10 Participants Participant exercised in a hot environmental temperature while wearing a surgical face mask High-intensity interval exercise with surgical face mask in a hot environment: Participants performed high-intensity interval exercise in a hot environmental condition while wearing surgical face mask
Peak Heart Rate Over the Course of High-intensity Interval Exercise	164 beats per minute Standard Deviation 20	164 beats per minute Standard Deviation 17	169 beats per minute Standard Deviation 16	169 beats per minute Standard Deviation 16

Adverse Events

No Mask Temperate

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Mask Temperate

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

No Mask Hot

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Mask Hot

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Christine Mermier

University of New Mexico

Phone: 5052772664

Email: cmermier@unm.edu

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place