The U.S. Department of Health and Human Services recommends through their physical activity guidelines that Americans perform muscle-strengthening, resistance-type (body weight, weights, elastic tubing) exercise at least twice weekly, in association with aerobic exercise—moderate-continuous and interval training—to achieve positive health benefits.
The benefits of resistance exercise include bone and muscle development and strength, improved cardiorespiratory health, especially with circuit training; reduced blood pressure (post-exercise hypotension); improved lipid profile (LDL-C), and glucose metabolism.
While the link to reduced cancer incidence with aerobic exercise is valid, similar evidence for resistance training is lacking.
In “Weight Training and Risk of 10 Common Types of Cancer,” appearing in the September issue of Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine, researchers from various groups within the National Cancer Institute sought to determine the association of weight training with the incidence of 10 common cancers.
Those cancers included: colon, kidney, bladder, breast, lung, non-Hodgkin lymphoma, pancreas, prostate, rectum, and melanoma.
The investigators used the NIH-AARP Diet and Health Study, which was established in 1995 to 1996. An initial questionnaire regarding demographics, medical history, and dietary behaviors was mailed to AARP members between the ages of 50–71 – residing in six US states and two metropolitan areas.
567,169 questionnaires were returned, which resulted in an 18% response rate. In 2004 to 2005, a follow-up questionnaire was mailed to the remaining participants to update information on lifestyle that included a more comprehensive assessment of physical activity. The follow-up questionnaire was completed by 313,363 participants.
According to the researchers, “our primary exposure was self-reported time spent per week on “weight training or lifting (include free weights and machines),” with 10 possible response options—none, 5 min, 15 min, 30 min, 1 h, 1 h +30 min, 2–3 h, 4–6 h, 7–10 h, and more than 10 h—in the follow-up questionnaire. This information was recoded into “no weight-lifting,” “low weight-lifting” (5 min to 1.5 h), and “high weight- lifting” (2–10+ h).
Based on the data extraction, the researchers said, “of the 10 cancer types examined in this study, weight-lifting was significantly associated with colon cancer only, which differs from aerobic physical activity’s reported benefits for many different cancer types.”
In conclusion, “weight-lifting was associated with lower risk of colon cancer, and possibly kidney cancer. These findings underscore the importance of resistance activity for health, including possibly for prevention of these cancers.”
Remember, you should always consult your physician before beginning any exercise, diet, or nutritional supplementation program.