TL:DR - There is no significant difference between running on a treadmill with or without a mask. Wearing a mask reduced this individuals aerobic capacity by 3.7%. They also experienced an overall reduction in heart rate and oxygen saturation (less than 1% change).
Independent Observational Study
Exercising with a mask… is it bad or is it good? There is growing safety concern that wearing a mask while exercising, especially on a piece of cardio equipment, is a violation of safety and will give you a trip straight to the hospital. Certainly during the Covid-19 pandemic some of our best efforts to reduce transmission are the requirements of face coverings and physical distancing. But when it comes to exercise, many rules have been thrown out the window for the sake of our physical and mental health. It seems to be a double-edged sword, Exercise is good for you and may help reduce the severity of the Corona Virus but at the same time we are putting ourselves in a high risk environment working out with individuals with no masks.
Compare the physiological effects of wearing a mask while performing moderate to vigorous exercise on a Treadmill.
Subject has a history of moderate to severe Asthma as well as seasonal allergies that restrict breathing and affect subjects' oxygen levels with varying degrees of severity. Subject has a 15 year history of moderate exercise but has been mostly inactive for the past 2 years.
Subject’s medical history was taken using a questionnaire. Subjects baseline biometric data was recorded prior to each exercise event. The subject performed two separate tests one without a mask and another with homemade 2 ply cloth mask. The subject's mask snugly fits over the nose and under the chin without loosening or falling under the nose while exercising. Each treadmill test follows the Standard Bruce Protocol, a standard test protocol in cardiology.
Standard Bruce Protocol:
The Bruce Protocol has been used in clinical exercise testing laboratories for approximately 40 years and is reportedly the most common protocol used to determine predictions of VO2 max. The Bruce Protocol consists of 3 minute stages, where the speed and grade both increase with each stage. The Subject is encouraged to provide a maximal effort but may stop the test at any time. VO2 is a standard measurement for an individuals highest rate of oxygen consumption during maximal or exhaustive exercise.
Heart rate and Oxygen levels were monitored at rest, during the test, and during recovery. Blood Pressure and breathing rate were taken at rest and immediately after stopping the test. Measurements were taken using a pulse oximeter and a standard blood pressure cuff. Heart Rate and Oxygen Levels were assessed and recorded at every 3 minute increment prior to the next stage and immediately following the subjects stopping point.
Interpretation of Results:
Both heart rate and oxygen saturation recordings showed no significant difference while wearing a mask. Estimated VO2 did not have a significant change but did result in a reduced capacity while wearing a mask. This was calculated by the difference in time to failure. The only notable difference was a lower average for both heart rate and oxygen saturation while wearing a mask. Wearing a mask did not have a significant effect on resting values nor on peak values while running the test. The only significant difference while wearing a mask is seen with breaths per minute. Breaths per miniature were taken immediately following failure of the test and there was a 16 breath per minute difference.
There are many possible factors that can influence breathing rate. Oxygen uptake and carbon dioxide output can drastically influence breathing rate. The volume of air you breathe in and out will determine how much oxygen you are supplying the cardiovascular system with. Shallow rapid breaths vs Deep slow breaths have a noticeable difference of oxygen uptake and in turn affect oxygen saturation. Energy levels in the body can have a major effect on breathing rate. When we reach a certain exercise intensity, our body produces usable energy through an anaerobic process which has a fast production rate to keep up with the demands of the exercise. During this anaerobic state we fatigue very quickly and at some point have to stop as our energy demands are higher than our production. After we stop, the body needs to produce energy both anaerobically(without O2) and aerobically(with O2). With this need, the body’s physiological response is to increase heart rate, breathing rate, and dilate the blood vessels allowing for more oxygen uptake in the muscles. As the body recovers and returns to normal heart rate and breathing rate can reduce rapidly due to an increased supply of oxygen. Finally the participants' decision to stop will influence their values if they decided to stop early and not achieve maximal results. Although there are many factors that can influence these changes, we do not have enough data to support the claim that wearing a mask will significantly impact our exercise routine on a treadmill.
The subject claimed to feel better with the test while wearing the mask, it is possible the subject felt more comfortable during the second test having completed one already. The subject did note that their exhaustion persisted and recovery time took longer. This may have coincided with the reduced breathing rate or with some degree of breathing restriction.
There are benefits to wearing a mask while exercising. You may have even seen someone or heard that person wearing a mask before this pandemic. Those masks are “Elevation Trainers” or “VO2 training masks” and these devices' sole purpose is to restrict the amount of oxygen that an individual breathes in during their exercise routine. The idea behind this is to force the body to adapt to a low oxygen environment. The body can adapt in multiple ways that benefit an athlete. These beneficial adaptations include more red blood cells as well as more hemoglobin to carry more oxygen in the bloodstream, greater number of mitochondria allowing your body to produce more energy, increasing lung capacity, and other benefits. These adaptations can occur in low altitude or oxygen rich environments with the help of a mask when worn consistently during training. However when the athlete stops using the altitude trainer, their body's adaptations can return to normal in a few weeks.
There are some negative benefits while wearing a mask and exercising such as increased cardio respiratory distress due to increased breathing and increased heart rate. Individuals with pre-existing conditions such as Chronic Obstructive Pulmonary Disorder(COPD) or Emphysema already have restricted airflow and further restricting airflow may be dangerous for the individual. Individuals with anxiety may find the exercise more stressful than normal and induce an attack that can lead to trouble breathing.
Regardless of the situation, whether you find it beneficial for your exercise routine or if you find it dangerous, you should take precaution while exercising with a mask on. The ideal thing to do is begin with light exercise to see how your body reacts to wearing a mask. Over time as you are more comfortable with a mask, you can increase your intensity to your regular routine.