Full-body compression gear makes your heart work harder

Quick look at a study just posted in the European Journal of Applied Physiology, from researchers at the University of Otago in New Zealand. They investigated the effects of full-body compression garments (Skins) on cyclists, looking in particular at three outcomes:

1. Did it make the cyclists faster?
2. What effect did it have on their body temperature?
3. What effect did it have on their cardiovascular workload?

To separate the effects of compression from the effects of wearing a full-body suit in reasonably warm temperatures (24 C), the subjects each did three trials: a control trial in gym shorts; a trial with “properly fitting” Skins; and a trial with oversize Skins. The results:

1. No difference in cycling performance
2. Skin temperature was higher by 0.5-0.9 C during exercise when wearing compression gear, but core temperature was unaffected.
3. Their hearts had to work about 5% harder with the compression gear on, and they finished with a heart rate 4-7% higher than in the control condition.

The authors make their skepticism clear pretty much from the start: the first sentence of the abstract is “Sporting compression garments are used widely during exercise despite little evidence of benefits.” They make several interesting points in the paper — for instance, the vast majority of “evidence” cited for increased venous flow and reduced venous pooling comes from studies of people (generally with some sort of circulatory condition) at rest. Do the same findings apply during exercise? It may be that the “calf muscle pump” — the squeezing of the calf that shoots blood back toward the heart, which supposedly gets a boost from compression socks — is already acting at maximal capacity during vigorous exercise.

Bottom line from this study: the garments didn’t really make much difference (the mild changes in temperature and cardiovascular function, though negative, weren’t enough to be a big issue). The authors are careful to note that the study has nothing to do with whether compression garments help recovery. But as far as wearing them during exercise, this certainly doesn’t change my opinion that wearing a full-body speed-suit while jogging on a hot summer day (and I see plenty of people doing that here in Sydney!) may look cool, but doesn’t do anything for your performance.