Exercise Heat Shock Proteins chemotherapy
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In September 2010, various newspapers reported the results of a laboratory trial from Ohio and some made the inappropriate conclusion that exercise before chemotherapy is ill-advised.
We know already from many excellent studies that exercise during and after chemotherapy is healthy, it reduces the risks of:
Furthermore, regular vigorous exercise has direct anticancer properties by stimulating the body to produce anti-cancer chemicals including IGF-1. There, therefore, has to be very good reasons to advise patients not to exercise. The recent study from Ohio reported that adding a chemical called heat shock protein (HSP) to cancer cells growing in a petri dish increase their resistance to chemotherapy by allowing he cells to heal themselves more efficiently. The author and many newspapers went on to suggest that exercise before chemotherapy should be avoided. Although an interesting academic experiment, this was based on the assumption that HSP can increase in humans after exercise. Here are the reasons why this advice cannot be supported.
Heat Shock Proteins (Heat shock factor-1)
These proteins are activated by the body in response to cellular stress such as attack from chemicals, high temperature, infection or lack of oxygen (hypoxia). The heat shock protein-1 activates another protein called Hsp-27 that helps to block cell death. It also interacts with a third protein, p21, which allows cells to repair themselves and keep dividing. Much of the research up to now has concentrated on how this mechanism protects normal issues such as the heart in times of hypoxic stress. It has also been implicated in the aging process. The main stimulus for the body to produce HSP is a raised temperature (associated with infection), lack of oxygen (such as a heart attack), steroid injections such as dexamethasone (routinely given with chemotherapy) and indeed chemical attack from chemotherapy.
People who exercise regularly tend to have
higher baseline HSP levels, and is one of the explanations why they tend to look younger.
There is some clinical evidence that vigorous exercise can increase levels HSP
especially if associated with a lack of oxygen, although not all experiments
agree with how much it would rise and what level of exercise is required. For example, a study from Toronto measured HSP in muscle in
mice while they were exercising, They found that there was no increase in levels
when mice where exercising normally on a wheel. Only those exercising anaerobically (sprinting) and simultaneously
heated to 40 degrees had any increase in their HSP – condition which would be
hard to emulate in humans. Test in humans also show that regular exercisers do
not tend to have a sudden rise rise in HSP when then exercise more vigorously
but blood levels can rise if strenuous exercise is taken in a previously
sedentary individual. Either way there is little information on whether
increased blood and tissue levels of HSP would actually increase levels within
cancer masses in humans.
The experiment involving breast cancer cells from Ohio, showed that adding HSP to the cancer cells in the petri dish made them more resistant to chemotherapy. Following this there was a media frenzy warning that exercise could diminish the killing effect of chemotherapy. They made no comment on the fact that, if indeed HSP were increased in the body, it also would also diminish the harmful side effect, including heart damage. And, although this has not been proven, I suspect the benefit in terms tissue protection would out way the tumour sparing effect - thus actually increasing the therapeutic ratio of chemotherapy. Certainly a therapeutic procedure called hyperthermia (used with chemotherapy and radiotherapy) suggests that heating the tissue actually kills more cancer cells without killing the normal cells.
In summary: There is no evidence, at all, that in humans exercise diminishes the chemotherapy effect. There are several benefits of exercising during chemotherapy. In view of the new Ohio experimental data more research is necessary to see if exercise may be a way to further increase the therapeutic ratio.
Practical advice: continue regular exercise during chemotherapy and afterward - consider joining a gym or/and a personal trainer. Although the evidence is poor for any risk, avoid extreme aerobic exercise (sprinting) 48 hours before chemotherapy especially in very hot climates/ rooms especially if you do not exercise regularly