Carrying excess weight is bad for your blood pressure in several ways, but if you can lose even a few of those excess pounds, your blood pressure can come down quite significantly.
The link between excess weight and high blood pressure
Being overweight increases the work load of your heart, which has to pump blood through a larger than normal volume of fatty tissue. Fat cells also release substances that have an adverse effect on the liver, increasing the level of inflammatory chemicals produced and making your arteries more likely to constrict. Hormone changes associated with carrying excess fat also promote fluid retention.
When 9,000 Finnish women aged 47-56 years were followed for five years, the results showed their risk of developing hypertension increased by 5% for each excess kilogram of fat they carried. A weight gain of 5 kg increased the risk of hypertension by 25%, but gains of more than 7kg increased the risk by a massive 65%.
Losing weight can lower a high blood pressure
The good news is that losing at least some weight can help to prevent your blood pressure from creeping up further and can bring your blood pressure down. Even after taking other factors into account, such as age, initial weight/height, exercise level, smoking and alcohol intake, a weight loss of 6.8 kg or more can reduce the risk of developing hypertension by 28% for middle-aged adults, and by 37% for older adults.
If you already have hypertension, losing a relatively small amount of excess fat will produce significant results. For each kilogram of weight lost, your blood pressure will fall by around 1/1mmHg in the short term. Longer term trials show that each 10kg of excess weight you can lose will reduce your blood pressure by an average of 6/4.6 mm Hg. Some people see significantly greater improvements with blood pressure reducing by as much as 10/20 mmHg with a weight loss of 10kg (22lb). This is by no means as easy to do as it sounds, however, and you will need lots of motivation, encouragement and support to achieve this.
Is it about exercise?
The blood pressure benefits of losing weight are not just due to increased levels of physical activity. This was shown in a study involving 133 sedentary, overweight adults with high normal blood pressure, and hypertension, who were asked to either exercise, take exercise and lose weight, or to carry on as before, with no diet or lifestyle changes.
In those who just exercised, without losing weight, average blood pressure fell by 4/4mmHg compared with those who did nothing. Those who both exercised and lost weight, however, saw their blood pressure come down by 7/5 mmHg compared with those who made no lifestyle changes. So, although exercise alone is effective in reducing blood pressure, losing weight enhances this effect.
When you are first diagnosed with hypertension, your doctor will usually suggest that you lose at least some excess weight as part of a general lifestyle plan which in most cases will include following the DASH diet and cutting back on salt intake. In many cases, losing excess weight can mean you avoid the need for antihypertensive medicines altogether.
If you are already taking BP medication, then weight loss can improve your blood pressure readings enough for your doctor to prescribe fewer medicines or lower doses. Don’t let your weight go too low, however, as this can also lead to long-term health problems. Aim to stay within the healthy weight range for your height.
What is an ideal weight?
Measuring weight isn’t as simple as just stepping on the scales, as it depends on factors such as your muscle build, bones density and body fluids as well as your fat stores. A weight of 75kg (11stone 11lb) may be ideal for one person but seriously overweight for another.
For greater accuracy, a way to estimate body fat stores was developed that uses the relationship between your height and weight to estimate body fat stores. Called the body mass index, or BMI, it is calculated by dividing your weight (in kilograms) by your height (in metres) and by your height in metres again. You don’t have to work this out yourself – use the free BMI calculator below which can use metric or imperial units. This gives a number, known as your Body Mass Index, or BMI, which is interpreted as follows:
Although BMI is a useful guide, it’s not a perfect measure of body fat and is not accurate for people who are less than five feet tall, or those with a lot of muscle mass. The BMI calculation tends to overestimate body fat in athletes and body builders with a muscular build, and to underestimate body fat in older people and those who have lost muscle mass.
It also takes no account of where you store your excess fat – those who store excess fat around their internal organs, giving them a large waist, have significantly more health problems, including high blood pressure, than those who store fat elsewhere. Even so, if you have high blood pressure, it offers a useful indicator of whether or not you would benefit from losing weight.
Powered by BMI Calculator
The ideal weight range for your height
Working backwards, the BMI of 18.5 to 24.9 Kg/M2 can be used to calculate the ideal healthy weight range for your height, as shown in the following table (calculations rounded up or down as appropriate). Find your height (in metres or feet) and read across to find the healthy weight range for your height (in kilograms or stones and pounds).
This relatively wide weight range takes into account a variety of body shapes.
If you are somewhere in the middle of the range, your weight should be fine.
If you are towards the upper limit of the weight range, aim to not let your weight creep up further.
If your weight is above the healthy range, aim to lose weight until you are back in the healthy range.
If your weight is below the lower limit of the range, talk to your doctor about whether you should try to put on weight.
How does your waist fit in?
If you store excess fat around your waist, you are twice as likely to develop hypertension and its complications, such as heart attack and stroke, as someone who stores excess fat around their hips.
Researchers have found that your waist size is a better indicator of your health than either your weight or your BMI. So, find a tape measure and check the size of your waist.
Find the bottom of your ribs and the top of your hips, and wrap your tape measure around your waist, midway between these points. Breathe out naturally, then make a note of your waist measurement.
You have a higher risk of health problems if:
- you are male and your waist size is more than 94cm (37 inches),
- you are female and your waist measures more than 80cm (31.5 inches).
For Asian men and women, the health risks increase from a lower waist size, and you need to take steps to reduce your level of abdominal fat if your waist measurement is greater than 90cm (36”) for a man, or above 80cm (32”) for a woman.
Researchers have found that men with a waist size larger than 102 cm, and women with a waist circumference larger than 88 cm, are more likely to develop high blood pressure, high cholesterol levels and diabetes than those with a slimmer waistline.
There is good news – waist size reductions of between 5 cm and 10 cm can significantly lower your blood pressure and reduce your future health risks. This is do-able with a combination of diet and exercise.
Losing excess weight
There is a lot of controversy over which type of weight loss diet is best. While traditional healthy eating guidelines have focussed on low fat diets, there is a growing recognition that these are not always helpful as they increase your relative carbohydrate intake. Carbs trigger release of insulin – the main fat storing hormone in your body – which is not that helpful. Following a low-fat diet also tends to lower your ‘good’ HDL-cholesterol and raise your circulating triglyceride levels. Researchers have also confirmed that when you reduce your overall fat intake below 30%, your liver produces a type of ‘bad’ LDL-cholesterol whose particles are smaller and denser, rather than larger and fluffier. As a result, a low fat diet may even increase the risk of heart disease in some people.
In contrast, a number of studies suggest that following a lower carbohydrate diet may promote weight loss as well as lowering systolic blood pressure (the upper reading) by between 1 mmHg and 10 mmHg. Lower carb diets also have beneficial effects on blood fat levels, reducing ‘bad’ LDL-cholesterol and triglycerides while raising ‘good’ HDL-cholesterol and improving glucose control.
While eating an extremely low carbohydrate diet does not suit everyone, a good compromise is to follow a low GI (glycemic index) diet or to follow a lower carb version of the DASH diet – simply cut down on the grains and eat more vegetables. I believe that most people with hypertension will benefit from cutting back on carbohydrates in general (and certainly the sugars and processed white versions of grains) and this is especially important if you also tend to store fat around your waist.
Although losing weight is important, it is vital that your weight does not yo-yo up and down. A study published in the European Journal of Clinical Nutrition in 2005 showed that, among 258 obese women aged 25-64 years, those who experienced at least five weight reduction cycles of at least 4.5 kg per cycle during the previous five years were significantly more likely to develop hypertension than those whose weight did not yo-yo. This was especially likely if they tended to store weight around their middle.
You can calculate how many calories you need per day, based on your gender, height, weight and activity level using the tool below. If you want to lose weight, aim to eat around 500 kcal less per day than you need, and exercise more to burn off more of the calories you eat.
My book, OVERCOMING HIGH BLOOD PRESSURE offers three, easy-to-follow programs of complementary medicine and self-care treatments to support conventional treatments. Different nutritional approaches are used to create Gentle, Moderate and Full-strength programs so you can decide which suits your lifestyle best. Each program offers daily menu plans, exercise routines and techniques from complementary medicine to help you make real, long-lasting changes to your health, and help you lose weight.
Click here for advice on choosing a blood pressure monitor to use at home.
See my recommended upper arm blood pressure monitors
Image credit: saje, tatiana popova / shutterstock