I just wrote a blog on this topic and included the most relevant paragraph to your question below:
OSHA gives a general recommendation for workplace temperature ranges to fall between 68-74 degrees Fahrenheit and humidity levels to range between 20-60%. Since these are pretty broad ranges, the International Fitness Association (IFA) developed more direction from the ranges recommended from both OSHA and the American College of Sports Medicine. IFA recommends that that gyms that provide aerobics, weight training, cardio, and Pilates should have an average temperature of 65-68 degrees Fahrenheit (18-20 degrees Celsius). The gym should also have a humidity level between 40% and 60% for these activities. http://www.gyminsight.com/blog/2013/08/optimal-temperature-volume-settin…
You can find all the resources I used on my post at the blog source provided. Off hand though, the most relevant source to your question is from the IFA and can be found at: http://www.ifafitness.com/health/temperature.htm
Hello Rena Sered,
Yes, there are guidelines: ACE Group Fitness Instructor Manual, Third Edition, 2011, states that the general fitness area room should be adjustable between 65-85 degrees F.
You may want to ask the participants at what temperature they are most comfortable.
NAPS 2 B Fit