A sedentary lifestyle has been shown to increase the risk of heart attack and stroke. Did you know that it is implicated in the development of breast cancer too? Studies showed that the most physically active women had a lower risk of breast cancer compared with women who were the least active. Regular physical exercise may protect against breast cancer due to hormonal influences such as reducing serum estrogens, insulin, and insulin growth factor-1 levels.
Exercise has positive effects on insulin levels.
The Women’s Health Initiative reported that higher insulin levels were associated with an increased risk of breast cancer in postmenopausal women who did not take menopausal hormone therapy. These women were not diabetic. You can influence insulin levels by a diet low in simple or processed carbohydrates, and sugar and by keeping your cortisol, the stress hormone in check. Any dis- stress will raise cortisol which will raise blood sugar, which will raise insulin.
Exercise has insulin lowering effects especially if you exercise regularly. Exercise increases insulin sensitivity which means you need less insulin to produce the same effect. The lower the insulin levels the lower the risk of breast cancer.
What type of exercise?
The point is the exercise has to be regular to be effective.
- Aerobic exercise increases insulin sensitivity especially in people who are obese or those who have type 2 diabetes. However, studies indicate that the activity has to be sustained.
- Resistance training also decreased insulin levels.
One study showed that a program consisting of :
- A warm-up by stretching and flexibility exercises for 10 minutes
- Walking for 30 m with maximum intensity 60% increase in heart rate
- Stretching in the seated position for 10 minutes
- 3 times a week for 8 weeks
Resulted in decreased
- BMI (weight to height – used to define normal, overweight and obese)
- Fasting blood sugar
- Slimmer waistline known as decreased waist and hip ratio
- Insulin and insulin resistance – this is good, high insulin and resistance can lead to heart disease, cancer and fat storage that increases inflammation, the root cause of most illnesses.
What was the most effective?
The combination of resistance and aerobic training had the best results by decreasing:
- Body fat mass
- LDL low-density lipoprotein the “bad cholesterol”
- Fat under the skin and the visceral fat in your liver and pancreas
- Leptin the hormone that makes you feel full – when it is high you get resistance and are tempted to over eat.
The combination of aerobic and resistance training increased:
- Lean body mass- the muscle that burns calories
- Adiponectin the hormone that if low can result in weight gain, diabetes and metabolic syndrome
Take Home Message
High insulin levels can lead to many health problems and a combination of regular, sustained activity using a combination of aerobic and resistance training can increase your insulin sensitivity and decrease your insulin levels. This may help you lose weight, lower your risk of many diseases including breast cancer and increase your quality of life.