Women, Heart Disease and Exercise
The leading cause of death in New Zealand is cardiovascular disease (CVD). It is fairly well known that men are more at risk than women from having a heart attack but many Kiwi women are not aware that CVD is also the leading cause of death for them as well.
A recent survey in the United States found that when women were asked to identify what the greatest threat to their health was, only 13% said heart disease or stroke. Most women perceived breast cancer as their greatest health concern and it is likely that if a similar survey was performed in New Zealand, Kiwi women would have similar answers.
Exercise and physical activity play a critical role in the prevention of CVD and also in the rehabilitation of a person who has suffered a heart attack or stroke. Before we discuss how activity helps our hearts to stay healthy let us look at the disease itself.
What is CVD?
CVD is a general term used to describe disease of the blood vessels (coronary arteries) that supply the heart with oxygen and nutrients. The coronary arteries become blocked with fatty deposits that reduce blood and oxygen flow to the heart muscle. The reduced oxygen supply causes chest discomfort. An artery that is partially blocked for a long period of time or an artery that is completely blocked with fatty deposit will result in the person having a myocardial infarction or heart attack. Once a person has had a heart attack, part of their heart muscle will have died and they will not regain function in that part of their heart ever again. These fatty deposits can also occur in the cerebral blood vessels that supply the brain. When a blockage occurs in the cerebral vessels, a person has a stroke and similarly will have residual effects because of the damage done to their brain.
What are the risk factors for CVD?
CVD is largely a lifestyle related disease. Many of the risk factors can be modified by changing your lifestyle. The modifiable and non-modifiable risk factors are listed below. Modifiable risk factors are the ones that you have the ability to change. Non-modifiable risk factors are those that you have no control over, you cannot change them.
Modifiable Risk Factors Non-modifiable Risk Factors
High blood pressure Male gender (although women have equivalent risk after menopause)
High cholesterol Family history of CVD, heart attack, stroke
Physical inactivity Age
45 years and over for men
55 years and over for women
Current smoker or given up in last 6 months
Diabetes
Obesity
Many women see these risk factors and believe that because men have been specifically identified as being at risk, that because they are female they are not. This is a huge misconception. If a 40 year old man is active with normal blood pressure and cholesterol, he quit smoking 10 years ago and is not overweight, then he is at less risk than a 40 year old women who has elevated blood pressure and cholesterol, who is not very active and is carrying 15kg of body weight more than she should.
Women are partially protected against CVD by their high oestrogen levels. When she reaches menopause her oestrogen levels drop and therefore a woman’s CVD risk increases to match that of a man. However, at any age, regardless of oestrogen concentration, if a woman has a number of the modifiable risk factors then her risk of having a heart attack or stroke is fairly high.
How do activity and exercise help?
A major factor in the development of CVD is high blood pressure and regular exercise provides a mechanism to reduce blood pressure. Frequent physical activity can reduce both systolic and diastolic blood pressure by between 6-10mmHg although at low exercise intensities the effect may not be as evident. Therefore, moderate to high intensity exercise is beneficial for people with high blood pressure but it is essential that they get a clearance from their doctor prior to commencing an exercise programme. In addition, if the person has known CVD or a number of CVD risk factors it may not be appropriate for them to exercise at even a moderate intensity without supervision so, again, medical clearance or participation in a specific cardiac exercise programme is recommended. The beneficial effects of exercise are not simply a reduction in pressure but also a reduction in the damage to arteries that constantly occurs in people with chronic high blood pressure. Arterial damage is thought to be the first step in the development of CVD therefore reducing mechanisms of damage is hugely beneficial to a person’s health.
In the next issue we will discuss in more detail how exercise is beneficial in the prevention of CVD but also how it is essential for rehabilitation after a person has had a cardiac event like a heart attack or a cardiac intervention like a heart bypass or angioplasty. If you would like more information in the meantime visit www.thecardiacclinic.co.nz or www.nhf.org.nz