Almost every personal trainer, instructor or other “expert” will insist that you cool down after exercising. This usually involves some light cardio and/or stretching. Some recommend 10 minutes or more and it’s often the last thing you feeling doing after a difficult workout. So is there any science behind the idea of a cool down?
Cool downs have been claimed to reduce delayed onset muscle soreness, increase performance, increase flexibility and reduce injury,. Let’s look at studies on each in turn.
Delayed onset muscle soreness:
One study had participants walk backward on an incline treadmill to cause delayed onset muscle soreness. Participants either had a 10 minute warm-up (walking forward uphill) a 10 minute cool down (walking forward uphill), both or neither. The researchers found that the warm-up reduced delayed onset muscle soreness, but the cool down had no effect.
Another study had professional soccer players either do 12 minutes of light running and 8 minutes of stretching (the cool down) or sit on a bench for 20 minutes after practice. The next day, the cool down group saw no improvements in anaerobic ability, heart rate or perceived exertion. The cool down group did see slight gains in the vertical jump though.
The same study on soccer players, perhaps surprisingly, found no benefits in flexibility to cooling down (even though stretching was performed during the cool down).
Dizziness and fainting:
During extended, vigorous exercise blood vessels expand in your legs to increase blood flow. Abruptly stopping exercise can cause blood to pool in your legs, increasing the chance that you will become dizzy and/ or faint.
If you engage in vigorous exercise like sprinting or a marathon a minute or two of light cardio afterwards is a good idea. Otherwise, there appears to be no real benefit to cooling down. There’s no harm in cooling down if you like doing it, but you might want to otherwise save a few minutes by going home early instead.
Herbert, Rob D., and Michael Gabriel. “Effects of stretching before and after exercising on muscle soreness and risk of injury: systematic review.” Bmj325.7362 (2002): 468.
Law, Roberta YW, and Robert D. Herbert. “Warm-up reduces delayed-onset muscle soreness but cool-down does not: a randomised controlled trial.”Australian Journal of Physiotherapy 53.2 (2007): 91-95.
Rey, Ezequiel, et al. “The effect of immediate post-training active and passive recovery interventions on anaerobic performance and lower limb flexibility in professional soccer players.” Journal of human kinetics 31 (2012): 121-129.
van Mechelen, Willem, et al. “Prevention of running injuries by warm-up, cool-down, and stretching exercises.” The American Journal of Sports Medicine21.5 (1993): 711-719.