For years coaches and sports medicine experts counseled athletes, professional and weekend types alike, to warm up before exercising and cool down afterwards. Is that good advice–or not?

The rationale was that warming up with calisthenics, brisk walking, or other activity helps ease the body into a strenuous workout and may reduce injuries. Cooling down is supposed to gradually reduce your heart rate and return your body to a state of rest, thus lowering the risk of soreness and even heart attacks. Or so the exercise physiology textbooks taught for decades.

The problem is, there’s little solid research backing up this advice, and much of what’s out there is conflicting. In terms of stretching, which many people include in their pre-exercise routines (though it’s technically not a warm-up, since it doesn’t raise heart rate much), most studies have found that it does not protect against exercise-induced injuries.

Cool on warm-ups

A review in the journal Sports Medicine tried to make sense of 25 years of research on the effect of warming up on the risk of injuries. The authors concluded that overall the weight of evidence suggests that a “warm-up and stretching protocol should be implemented prior to physical activity.” However, they acknowledged that studies’ conclusions were all over the map, and called for more research.

Most of the studies have been small and focused on certain types of athletes, age groups, and just men or women. What helps a 25-year-old female triathlete, for example, may not help a 75-year-old man who cycles two or three times a week.

Research has also been inconsistent on the effect of warm-ups on performance. An Australian study in the European Journal of Applied Physiology, for instance, found that warm-ups that included some static stretching actually decreased muscle power among young people doing vertical jumps. But an analysis in the Journal of Strength and Conditioning Research found that warm-ups improved performance.

Lukewarm about cool-downs

Good studies on the potential benefits of cooling down are even more scarce. While it feels right and sensible to gradually diminish the intensity of your workout, there hasn’t been much research showing benefits. Still, the American College of Sports Medicine (ACSM) recommends cooling down because it lowers heart and breathing rates and helps prevent pooling of blood in the legs, which can cause light-headedness and fainting. In particular, ACSM advises people taking medication for hypertension to cool down, since some of these drugs can cause blood pressure to drop even lower following an abrupt end to vigorous exercise.
Bottom line: Regular exercise has many proven health benefits; warming up and cooling down do not. Still, if you enjoy doing them and they feel good, there’s little or no downside. In fact, many people find they get a psychological, if not physical, boost from easing into and out of vigorous exercise, and who can argue with that?