In a time of ever-changing workout trends, no exercise seems to go without being renamed, revamped or reinvented. Indoor cycling, for example, started with bikes on trainers and since its conception in 1992 as a group training class, studios have added yoga, light weights and other modalities to sell the idea of a “full body workout.” Heated rooms seem to be the newest trend to find its way into the cycling class in studios across the country. Instructors are implementing a heated room during a ride touting that the more you sweat, the better the workout and consequently, the better the results. Unfortunately, this is an antiquated and possibly dangerous theory that is not founded on any science. In fact, indoor cycling under heated conditions can, and will, cause a reduction in exercise performance. With that said, every instructor should be aware of thermoregulation during exercise, how it changes with the heat index and the guidelines by which to safely coach a ride.
Thermoregulation in a nutshell is the body’s ability to regulate temperature when ambient temperature is different. When exercising in average conditions the body can efficiently adjust to the increase in body temperature. Our body’s cooling mechanism is through sweat, which as it evaporates and the skin cools down, so does the blood and therefore the body. However, as the external temperature increases, the body’s ability to cool down becomes less and less effective. As the body sweats and loses fluids, there is also a loss in blood volume. The lack of volume makes the heart work harder to get blood to the working muscles. In the case of cycling, if a rider cannot sufficiently put back the fluids lost and cool down, dehydration sets in and, as studies have shown, mental and physical performance are adversely affected. Now, add heat index to the equation.
Heat index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature. In other words, if ambient temperature is 80 degrees Fahrenheit, it could actually feel to the human body 87 or above due to humidity. How this translates into a cycling room is simple. Room temperature is set at 70. Add 30 to 50 sweating riders and no air or fans, and the temperature of the room is now 75 to 80 degrees. In a crowded cycling room with temperature set to 80, no air or fans and the heat index can reach up to 88 and above. Now, although the idea of a hot, sweaty driven class sparks the hope of losing more weight, the body does not act accordingly. Actually, the higher humidity makes sweating less effective to cool down the body internally. According to NOAA (National Oceanic Atmospheric Administration), “caution” should be used when exercising in 80 degrees Fahrenheit heat index and above; “extreme caution” when at 91 and above; it is “dangerous” when 104 and above; and you put yourself in “extreme danger” when 124 and above.
First priority of any instructor and studio is to provide a safe environment to ride. American College of Sports Medicine (ACSM) puts out a guide by which any cycling studio and their respective classes are to follow. (1)
Facilities should provide all physical activity spaces with sufficient air circulation and fresh makeup air (i.e., outside air) which will allow the facility to maintain air quality, room temperatures, and humidity at safe and comfortable levels during times of physical activity.
Air circulation is one of the most critical elements when designing and operating a health/fitness facility. When a room is filled with members and users exercising at a moderate to high intensity, the heat and humidity load increases dramatically. This can place an increased level of heat stress on the members and users and may result in dehydration, heat exhaustion, heatstroke, or (in rare instances) cardiovascular emergencies. In addition to the increased heat load that can result from improper air circulation, a risk of poor air quality exists that can expose members and users to airborne pathogens that can increase the risk of respiratory disorders or other airborne illnesses. Facilities can provide sufficient air circulation by taking into consideration the following factors:
* Maintain relative humidity at 60 percent or lower in all physical activity spaces. Ideally, a relative humidity level of 50 percent or lower is the desired goal, but maintaining levels below 60 percent is necessary.
* Maintain air temperature for all physical activity areas between 68 and 72 degrees F (20 and 23 degrees C). The key is to maintain these temperature ranges whether the room is empty or fully occupied by members and users who are engaging in moderate to vigorous physical activity. This guideline refers to the fact that the heating, ventilation, and air-conditioning (HVAC) system within the facility should have the capability to adjust airflow to meet the demands of each space.
These guidelines are put in place for no other reason than to protect any rider (regardless of their athletic ability). Any successful workout, no matter what themodality comes most successfully from the inside out not the outside in. The decision to ride in any atmosphere is under the discretion of the rider. However, doing so with eyes wide open and a little bit of education can make the difference between a negative loss to a positive gain.
(1) ACSM Health/Fitness Facility Standards and Guidelines, ACSM (Human Kinetics, 2007), page 35
Hot Stuff: Thermoregulation. spinning.com
Exercising in the Heat. Dr. Stephen D Ball, Ph.D., Nutrition and Exercise Physiology, University of Missouri Extension.
Heat Index. Wikipedia.org
Ask the expert: What if a teacher won’t allow air- conditioning in a Spinning Class? Jennifer Sage on May 31st, 2016. Indoor Cycling Association