Cardiovascular diseases — such as heart disease and stroke — are the leading cause of death globally, responsible for 17.9 million deaths per year in 2019, while cancers were responsible for 9.6 million deaths in 2017. Physical activity — particularly when it is moderate-intensity — is known to reduce the risk of cardiovascular disease and cancer, and the NHS recommends that adults do at least 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity a week.
To explore the amount of physical activity necessary to have a beneficial impact on several chronic diseases and premature death, researchers from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge carried out a systematic review and meta-analysis, pooling and analysing cohort data from all of the published evidence. This approach allowed them to bring together studies that on their own did not provide sufficient evidence and sometimes disagreed with each other to provide more robust conclusions.
In total, they looked at results reported in 196 peer-reviewed articles, covering more than 30 million participants from 94 large study cohorts, to produce the largest analysis to date of the association between physical activity levels and risk of heart disease, cancer, and early death.
The researchers found that, outside of work-related physical activity, two out of three people reported activity levels below 150 min per week of moderate-intensity activity and fewer than one in ten managed more than 300 min per week.
Broadly speaking, they found that beyond 150 min per week of moderate-intensity activity, the additional benefits in terms of reduced risk of disease or early death were marginal. But even half this amount came with significant benefits: accumulating 75 min per week of moderate-intensity activity brought with it a 23% lower risk of early death.
Dr. Soren Brage from the MRC Epidemiology Unit said: “If you are someone who finds the idea of 150 minutes of moderate-intensity physical activity a week a bit daunting, then our findings should be good news. Doing some physical activity is better than doing none. This is also a good starting position — if you find that 75 minutes a week is manageable, then you could try stepping it up gradually to the full recommended amount.”
Seventy-five minutes per week of moderate activity was also enough to reduce the risk of developing cardiovascular disease by 17% and cancer by 7%. For some specific cancers, the reduction in risk was greater — head and neck, myeloid leukaemia, myeloma, and gastric cardia cancers were between 14-26% lower risk. For other cancers, such as lung, liver, endometrial, colon, and breast cancer, a 3-11% lower risk was observed.
Professor James Woodcock from the MRC Epidemiology Unit said: “We know that physical activity, such as walking or cycling, is good for you, especially if you feel it raises your heart rate. But what we’ve found is there are substantial benefits to heart health and reducing your risk of cancer even if you can only manage 10 minutes every day.”
The researchers calculated that if everyone in the studies had done the equivalent of at least 150 min per week of moderate-intensity activity, around one in six (16%) early deaths would be prevented. One in nine (11%) cases of cardiovascular disease and one in 20 (5%) cases of cancer would be prevented.
However, even if everyone managed at least 75 min per week of moderate-intensity physical activity, around one in ten (10%) early deaths would be prevented. One in twenty (5%) cases of cardiovascular disease and nearly one in thirty (3%) cases of cancer would be prevented.
Dr. Leandro Garcia from Queen’s University Belfast said: “Moderate activity doesn’t have to involve what we normally think of exercise, such as sports or running. Sometimes, replacing some habits is all that is needed. For example, try to walk or cycle to your work or study place instead of using a car, or engage in active play with your kids or grandkids. Doing activities that you enjoy and that are easy to include in your weekly routine is an excellent way to become more active.”
The research was funded by the Medical Research Council and the European Research Council.
What counts as moderate-intensity physical activity?
Moderate-intensity physical activity raises your heart rate and makes you breathe faster, but you would still be able to speak during the activity. Examples include:
- Brisk walking
- Dancing
- Riding a bike
- Playing tennis
- Hiking
