Exercise …. Ugh, maybe later.

Maybe you might want to think again. Two recent articles from the Dana-Farber Cancer Institute (J Clin Oncol 2006; 24: 3527 – 3534; 3535 – 3541) have reported that physical activity has a positive impact on the course of the disease in someone with colorectal cancer. In the first article they studied 573 women with stage I to III colon cancer. These women had surgery and chemotherapy for their colon cancer. The researchers monitored the level of physical activities taken by these women and looked at the possible connection of physical activity and cancer-specific mortality (death) and overall mortality. Those women who had at least 18 metabolic-equivalent task (MET) hours per week of physical activity had better outcomes than those who had <3 MET hours of activity. The colorectal cancer-specific mortality and overall mortality for these ‘18 MET’ active women was 61% and 57%, respectively, less than the ‘3 MET’ women. The level of physical activity before the diagnosis of colorectal cancer was not predictive of the post surgery mortality. However, women who increased their post-treatment level of physical activity to above the pre-diagnosis activity level, experienced approximately 50% less colorectal-specific and overall mortality than those who maintained their pre-diagnosis activity level only. In the second article the same researchers studied 832 patients with stage III colorectal cancer (stage III cancer is when the colon cancer has spread to the surrounding lymph nodes but not to other sites such as the liver or lungs). These patients had been treated with surgery and chemotherapy for their condition. Those patients who had at least 18 MET hours per week of physical activity were found to have about a 50% better overall survival than those with <3 MET hours of activity.

18 MET hours of activity sounds like a lot to you, right? Not really. The more vigorous the physical activity, the higher the number of METs you get per unit time. For example, running and bicycling are considered vigorous exercise and can be defined as activity requiring 6 METs or more (≥ 6 fold increase above the resting metabolic rate). A moderate form of exercise such as walking (depending on pace) requires an energy expenditure of 2 – 4.5 METs. If you perform 45 minutes of vigorous exercise once a week, you will have earned yourself 5 MET hours. If you want the slower pace, then earn the same number of METs by having 1.5 hours of brisk walking once a week. It is that simple!

Indeed, it would be a sad fact if you need to develop a stage I or III colorectal cancer before you are prodded into regular physical activities. The increased incidence of obesity worldwide is in part due to reduced physical activity or exercise. Obese individuals experience an increased risk of a hotchpotch of health problems such as high blood pressure, heart disease, diabetes, high cholesterol, sleep disturbance problems such as sleep apnoea, arthritis, back pain and increased risk of colon and uterine cancers. Obese people are likely candidates to develop metabolic syndrome. please make the words metabolic syndrome life and insert the hyperlink to my archive article  The metabolic syndrome is associated with a 2 fold increase in the risk of developing cardiovascular disease and a 5 fold increase in developing type 2 diabetes. An old study from Harvard Medical School (JAMA 1999; 282: 1433 – 1439) examined the effect of exercise on the risk of developing type 2 diabetes in 70,102 nurses over an 8-year period. In women whose only form of exercise was walking,  0.6 – 2.0 MET hours per week led to a 9% reduction in their risk of developing type 2 diabetes. If you increased the weekly METs to 3.9 – 9.9, the reduction in risk was 31%.

Over a 10-year period, 1989/91 to 1999/2001, the average distance walked by people living in London had decreased by 15%! I would hazard a guess that the amount of food consumed did not decrease by the equivalent percentage. Just think what that would do to your waistline and health!

The next time you are about to press the ‘up’ button for the lift (or elevator), stop! Turn round and take the stairs instead. In the evening just before you sit down to watch the TV, hide the remote control. When you need something from your ‘7 eleven’ convenience store round the corner, leave the car and walk. You will be surprised how fast you clock up those METs!