Saunas induce a unique type of stress in individuals known as heat stress. When the body activates the stress system to respond to heat stress some of the same systems that are used during physical exercise, for example, are also activated.
Mentioned in a previous post was the fact that hyperthermia has been demonstrated to be able to help muscles recover more rapidly and with less oxidative stress after periods of immobilization.
Here’s an interesting study that demonstrated that sauna use specifically might be able to help prevent muscle atrophy from occurring in the first place, and not just assist in the recovery of lost muscle.
See the abstract below:
This study tested the hypothesis that elevation of heat stress proteins by whole body hyperthermia is associated with a decrease in skeletal muscle atrophy induced by reduced contractile activity (i.e., hindlimb unweighting). Female adult rats (6 mo old) were assigned to one of four experimental groups (n = 10/group): 1) sedentary control (Con), 2) heat stress (Heat), 3) hindlimb unweighting (HLU), or 4) heat stress before hindlimb unweighting (Heat+HLU). Animals in the Heat and Heat+HLU groups were exposed to 60 min of hyperthermia (colonic temperature ∼41.6°C). Six hours after heat stress, both the HLU and Heat+HLU groups were subjected to hindlimb unweighting for 8 days. After hindlimb unweighting, the animals were anesthetized, and the soleus muscles were removed, weighed, and analyzed for protein content and the relative levels of heat shock protein 72 (HSP72). Compared with control and HLU animals, the relative content of HSP72 in the soleus muscle was significantly elevated (P < 0.05) in both the Heat and Heat+HLU animals. Although hindlimb unweighting resulted in muscle atrophy in both the HLU and Heat+HLU animals, the loss of muscle weight and protein content was significantly less (P < 0.05) in the Heat+HLU animals. These data demonstrate that heat stress before hindlimb unweighting can reduce the rate of disuse muscle atrophy. We postulate that HSP70 and/or other stress proteins play a role in the control of muscle atrophy induced by reduced contractile activity. (via.)