Part 2 of the 3-part series on measuring your health.
While there is still a lot of debate about which measure most accurately predicts risk of cardivascular and other chronic diseases, it has been shown that each of these – BMI, waist circumference, and waist-to-height ratio – are all useful guides.
If you haven’t already, read part 1 of this 3-part series: Measuring fat, go through the health checklist and record your answers on a piece of paper. In part 2, we cover measuring your heart health.
Whether you are overweight or not, it’s helpful to have some idea about how you’re going in terms of the health of your heart and blood vessels. After all, cardiovascular disease has been killing Kiwis for longer than we’ve had an obesity explosion. Measuring your blood pressure and cholesterol levels are the two simplest ways for your GP to check the health of your heart and blood vessels. And a really simple measure that you can do at home is your resting heart rate.
Resting heart rate
The best time to measure your resting heart rate is first thing in the morning before you get out of bed. Use your index and middle finger; don’t use the thumb as it has its own pulse so you might double count! Find the pulse on the inside of your wrist and put your fingers on the thumb side. Starting from the first beat at zero, count the beats for one minute. (If you want to count for 30 seconds and double it, that will be close enough.)
Generally we’re told that 60-80 beats per minute is considered normal, but the lower end is better. It’s not uncommon for athletes to have resting heart rates below 60. Your risk of cardiovascular disease and death from other diseases decreases as the rate decreases. People with a resting heart rate below 60 are three times less likely to die (from any cause) than those with a heart rate over 90.
Is it better to be fit and fat, or unfit and thin?
While being overweight and being physically active are both linked to long-term health (independently of one another), being active may have a more significant effect than being thin. So if you are overweight and you find the fat hard to shift, do not despair. Probably the single most important thing you can do is to become physically fitter. And if you are a thin couch potato, don’t sit there smiling smugly. It’s not all about the lack of ‘fatness’; fitness is important too. Studies have shown that people who are physically active have a lower risk of developing cardiovascular disease or cancer compared to sedentary people, irrespective of their BMI.
High blood pressure, also called hypertension, is often called the ‘silent killer’ because many people don’t know they have it. It’s not a disease in itself, and by itself it won’t kill you, but it is strongly associated with the development of diseases that can kill you. So think of it as an early warning system. Of course you’ll need to have it measured first, which is a very simple and pain-free procedure that can be done at your GP clinic.
When your blood pressure goes up it means that your heart must work harder and damage can occur in blood vessels. Often you’ll hear ‘120 over 80’ quoted as a healthy blood pressure. That’s about right for young men; young women can be 8-10mmHg lower than that, and people who exercise regularly tend to have lower blood pressures than those who don’t. The first number (systolic pressure) is the highest pressure in the arteries when the heart contracts and the second number (diastolic pressure) is the lowest pressure in the arteries just before the heart starts to contract again. It’s measured in millimetres of mercury: mmHg.
Blood pressure is considered to be high when the top number is 140mmHg or more or the bottom number is 95mmHg or more. To be diagnosed with high blood pressure you’ll need to have several readings. It’s also important to ensure you’re not displaying ‘white coat syndrome’: some people get anxious about having their blood pressure taken, which can increase their blood pressure!
It’s also possible to have low blood pressure, but this is not associated with the development of any chronic diseases. In fact, healthy people with blood pressure at the lower end of the normal range tend to live longer than those at the higher end. So if your blood pressure is increasing over time, even if it hasn’t reached the arbitrary cut-off for a diagnosis of hypertension, you might want to think about making some positive changes to your diet and exercise regime.
Fats in the body are called lipids, and to have your blood lipids measured you need to do a fasting blood test. Your GP will send you for a test when they judge it advisable to check; this may be if you have other health risk factors like being overweight, or even just increasing age. High cholesterol levels can lead to the development of atherosclerosis, or hardening of the arteries; this is where fatty deposits develop in the walls of arteries, which can reduce or block the blood flow. This can affect the heart, brain, kidneys or other vital organs, and legs.
When you have your cholesterol tested, HDL cholesterol and LDL cholesterol and triglycerides are measured and all the numbers reported on are meaningful in terms of establishing your risk of developing cardiovascular disease.
Optimal mesaures are:
- Total cholesterol <4mmol/L
- LDL cholesterol <2mmol/L
- HDL cholesterol >1mmol/L
- Total/HDL ratio <4mmol/L
- Triglycerides <1.7mmol/L
There’s a direct relationship between high cholesterol levels and the risk of developing cardiovascular disease. That means between about 4-8mmol/L total cholesterol, the higher the reading, the greater the risk.
So again, don’t wait until the level gets to what you might arbitrarily decide is a scary number; any increase should indicate it’s time to make some changes. See Choleterol: Your questions answered for more about cholesterol.
Blood glucose levels
Diabetes diagnosed when the pancreas can’t make enough insulin and glucose levels in the blood increase beyond normal levels. This increases the rate of atherosclerosis, or hardening of the arteries, and people with diabetes have an increased risk of blood clots, heart attack or stroke.
Pre-diabetes, or impaired glucose tolerance (IGT), is the stage between normal blood glucose levels and a diagnosis of diabetes. There are no symptoms at this stage, but like other measures it operates along a continuum, so think of it as a warning to make changes now. Having your glycated haemoglobin (HbA1c) level tested provides a measure of your glucose levels over the previous six to eight weeks. Discuss with your GP whether a test would be useful for you.
What your HbA1c levels mean:
- ≥ 50 mmol/mol indicates probable diabetes (but does not confirm a diagnosis by itself)
- 41-49 mmol/mol suggests prediabetes/insulin resist
- ≤40 mmol/mol is normal
The good news is that being a healthy weight, having a healthy diet and doing physical activity all help with both the prevention and treatment of high blood pressure, high cholesterol and IGT or type 2 diabetes. See
How do adult Kiwis measure up?
BMI: 1 in 3 is classified as overweight (men 40%, women 28%) and 1 in 5 is obese (for men and women).
BP: 1 in 5 of us has been told by a doctor we have high blood pressure (there will be more undiagnosed) and two-thirds of us have taken drugs for it. That’s 13% of the adult population taking drugs for something that is strongly influenced by diet and exercise.
Cholesterol: 1 in 6 has been told by a doctor we have high cholesterol (and there will be more who have not been tested). Nearly half of those take drugs for it. That’s 7% of the adult population taking drugs for something that, in most people, is strongly influenced by diet and exercise.
Diabetes: 1 in 23 of us has been diagnosed with diabetes (and there will be more who have not been tested).
Physical activity: Around 3/4 of us claim to be physically active for at least 2 1/2 hours a week (men do better than women). 1 in 8 were physically active for less than 30 minutes in a week.
Vegetables: Only 2/3 of us eat the recommended three or more serves of vegetables each day (women do better than men).
Fruit: Just 1/2 of us eat the recommended two or more serves of fruit each day (women do better than men).
Did you know? It has been estimated that a human heart will, on average, beat for around 30 x 108 per lifetime. That’s 3,000 million times. So the slower it’s beating, the more time you may have. (As long as it doesn’t slow to a stop!)