Could 90 minutes of housework cut your heart disease and stroke risk?
News reports suggest that if you do 90 minutes of housework a day you could significantly cut your chances of developing heart disease and stroke. But is it time to grab a mop? We look behind the headlines.
The research, published in the BMJ, analysed existing studies, and found that – while lower levels of physical activity still had benefits – higher levels of total physical activity were significantly associated with lower risk for five diseases: breast cancer, colon cancer, diabetes, coronary heart disease (CHD) and ischaemic stroke (the most common type of stroke).
Some newspapers reported that the research means we need to do more physical activity than the recommended amount. Adults should aim to be active daily, every little helps to reduce your risk of cardiovascular disease. Current daily guidelines say that in a week, your activity should add up to at least 150 minutes of moderate intensity activity (or 75 minutes of vigorous intensity activity spread across the week) in blocks of at least 10 minutes.
The study found that compared to people who are inactive, people in the highly active category (with 8,000 MET minutes/week or more) had a 14 per cent lower risk of breast cancer, 21 per cent lower risk of colon cancer, 28 per cent lower risk of diabetes, 25 per cent lower risk of CHD, and 26 per cent lower risk of ischaemic stroke, the researchers concluded.
People in the highly active category had a 25 per cent lower risk of CHD, and 26 per cent lower risk of ischaemic stroke
MET (metabolic equivalent) is a measure of how much energy you’ll burn doing a certain physical activity, and is used to express the intensity of an activity. Walking slowly for 30 minutes does not burn the same number of calories as a 30-minute high intensity spin class, so although they are both classed as 30 minutes of physical activity there are differences in the intensity and the amount of energy used. METs (level of energy burnt) can be multiplied with the amount of time spent doing the activity to make MET minutes.
The analysis looked at 174 articles: 35 for breast cancer, 19 for colon cancer, 55 for diabetes, 43 for coronary (ischaemic) heart disease, and 26 for ischaemic stroke (with some articles included for more than one condition).
The researchers concluded that people who achieve total physical activity levels several times higher than the current recommended minimum level have a significant reduction in the risk of the five diseases studied.
The BHF view
June Davison, Senior Cardiac Nurse at the British Heart Foundation, said: “In the UK, it’s recommended that adults are active every day and do at least 150 minutes of moderate physical activity per week. But this study suggests even higher levels of physical activity would significantly lower the risk of developing a number of diseases, including heart and circulatory disease and breast cancer. We already know that there are additional health benefits with doing more than 150 minutes but in the UK nearly two in five adults don’t achieve the minimum recommendation.
The first step is to increase the number of people achieving 150 minutes of exercise a week
Senior Cardiac Nurse
“When setting guidelines there needs to be realistic target of what people are be able to achieve. Therefore the first step is to increase the number of people achieving 150 minutes of exercise a week and hopefully Rio 2016 will inspire many of us to take up a sport. Being physically active not only reduces our risk of heart disease and other conditions, including cancer, but can also improve our mental health and wellbeing.”
The story featured widely in the national media, including in The Telegraph, The Guardian, Independent, Express, Mail and others.
The Telegraph article could be misleading as it states “a round of housework each day significantly lowers the risk of developing five deadly diseases”. However, what's not obvious from the headline is that "one round of housework" would have to last 90 minutes. The study actually recommends that the 90 minutes of daily physical activity can include housework but is made up of 10 minutes’ stair climbing, vacuuming for 15 minutes, gardening for 20 minutes, running for 20 minutes and walking or cycling for 25 minutes.
The Guardian headline, ‘WHO's recommended level of exercise too low to beat disease – study,’could put people off exercise if they feel that, to have any real benefit, they have to have a higher level of activity. It’s important that we meet the existing physical activity target, before we increase it further. News stories that suggest people need to do even more exercise to get health benefits, may put off the 2 out of 5 adults who don't currently meet the guidelines for minimum physical activity levels.
A strength of the analysis is that it included a wide range of physical activity, including housework and other activities we often don’t class as exercise
A strength of the analysis is that it included a wide range of physical activity, including housework and other physical activities that we often don’t class as exercise.
Something that they didn’t look at in this study was whether the risk reductions would be different with short duration intense activity or longer duration light activity.
Moreover, the search for these articles was limited to two databases and studies published in English. Therefore the researchers may have excluded some relevant research. There may also have been some publication bias, in that the research papers chosen are not representative of all of the research available.