~Dr. Gabe Mirkin's Fitness and Health e-Zine
A review of 170 animal and human studies shows that regular exercise is associated with reduced cancer risk, particularly for the types of cancers that are associated with unhealthful lifestyles, such as those of the breast, colon, prostate, lung and endometrium (J Nutr, 2002 Nov;132(11 Suppl):3456S-3464S). Exercise helps to prevent cancer by reducing causes of inflammation: overweight, excess calorie intake, high blood sugar, high insulin and insulin-like growth factor-1, high estrogen, and overactive and depressed immune function.
The most likely reason why exercise reduces cancer risk is that it reduces an overactive immunity (Exerc Sport Sci Rev, 2015;43(3):134-142). Many studies show that exercise reduces markers of an overactive immune system that are also necessary for cancer growth: interleukin-6, tumor necrosis factor-a, and monocyte chemoattractant protein 1.
If you do not exercise, I recommend that you start an exercise program that may protect you from certain cancers and will also help to protect you from obesity, diabetes and heart attacks. Be aware that exercise can cause heart attacks in people who already have blocked arteries, so check with your doctor, particularly if you have any markers for arteriosclerosis: high blood pressure, cholesterol or blood sugar, or a lot of belly fat (more than three inches when you pinch the skin over your belly).
If you haven't exercised for a while, just go out every day and walk, jog or cycle for a short time, until your legs start to feel heavy or sore, and then quit for the day. Try to do this every day, but take days off when your legs feel sore. As you continue to move a little each day, you will gradually be able to increase the time you can spend exercising until you are able to exercise at low intensity every day for 30 minutes without feeling sore.
Fitness requires some degree of intensity. Whenever I see people reading while walking on a treadmill, I just shake my head. You have to damage muscles to make them larger and stronger, and you have to get short of breath to increase your ability to take in and use oxygen.
On the first day, warm up by walking, jogging or pedaling at a very slow rate for five to 10 minutes. Then gradually pick up the pace and when your legs start to burn, hurt or feel heavy, slow down. Do not use a clock, but when your legs feel recovered, pick up the pace again. Slow down at the least sign of discomfort. Do this until your legs start to feel heavy or tired and then quit for the day.
On the next day just go very slowly, or take the day off if your legs feel unusually sore.
Try to establish a training regimen in which on one day, you take a harder workout by alternating intervals of slow and fast movement, and on the next day, you go slow. Try to exercise for about half an hour each day. These alternating stress-and-recover workouts can make you very fit, help to prevent disease and prolong your life.