A new study found that daily heat treatments applied locally to muscle during 10 days of immobilization prevented the loss of mitochondrial function, increased heat shock protein levels, and attenuated skeletal muscle atrophy by 37% compared to sham control in a small trial in humans.
I am really glad to see this replicated now in humans. There’s were two similar studies that I covered in past videos, which showed that whole body heat treatment (similar to a sauna) prevented muscle atrophy and increased muscle regrowth after immobilization, however, these were done in mice. The difference is that this shows a pretty similar phenomenon in humans! This isn’t too surprising. The main reason for that is because the mechanism in animal research was already all worked out. The prevention of muscle atrophy and muscle regrowth in mice was shown to be dependent on the robust activation of heat shock proteins. These proteins are highly conserved in humans in function, playing an extremely apparent similar molecular role. More importantly, we already knew from prior research that heat shock proteins increase by ~50% after 30 minutes in a 163 ºF (73 ºC).
The results of this new study have important implications. While exercise interventions remain the most effective strategy to maintain or increase muscle mass and respiratory capacity, during periods of immobilization due to injury or for other reasons exercise can become more challenging. Heat therapy through modalities such as a sauna or even local heating (as is the case in this study) may ultimately serve as a very useful alternative or adjunct therapy to maintain skeletal muscle metabolic function and preserve muscle mass!