Intense exercise can help cancer cells survive treatment and lead to disease recurrence. This staggering statement is the result of a research study published in Molecular Cancer Research (2010; 8 [10], 1399–412). Stress, including the physical stress of intense exercise, seems to activate a protein that enhances the ability of cancer cells to survive treatments such as chemotherapy and radiation. This protein, called heat shock factor-1, is induced by stress. The research team found that Hsp27, a protein activated by heat shock factor-1, stopped the cancer cells’ death even after radiation had damaged the cells’ DNA.

“One of the known inducers of this factor is exercise,” lead author Govindasamy Ilangovan, MD, associate professor of internal medicine at Ohio State University, told Science Daily. “I am not against exercise, but the timing is critical. It looks like any intense or prolonged physical activity a couple of days before the start of cancer therapy is highly risky.”

This study was in vitro and has not been verified with living subjects, but the ramifications leave fitness professionals in a quandary. Multiple studies demonstrate the benefits of exercise for those undergoing cancer treatments. Exercise itself is a great stress reliever. No researcher suggests that cancer patients should stop exercising. Until more research clarifies this issue, here are some recommendations for fitness professionals working with clients who have cancer:

  • Have your client get an exercise prescription. Offer to speak with the client’s physician so you can be clear on the intensity and duration of the exercise.
  • Plan a detailed workout schedule; arrange for your client to take a rest from working out for 2 days before chemotherapy or radiation.
  • Have your client wear a heart rate monitor to keep an accurate gauge of the workout’s intensity.
  • Encourage your client to attend a gentle yoga class as a good alternative source of stress release.
  • Incorporate relaxation techniques such as meditation, visualization and deep breathing into each training session.

Janet Weller RN, CES, is an IDEA-recognized personal trainer and group fitness instructor.