Wednesday October 17 2012
Men who played football regularly had lower blood pressure
There was welcome news for footy enthusiasts in the Daily Mail today, as the paper reported that “playing football is the best way for middle-aged men to tackle high blood pressure”
This headline stems from research looking at previously inactive middle-aged men with mild to moderate high blood pressure (above 140/90 mmHg).
The men were split into two groups:
- the ‘football group’ – where men were asked to play recreational football (for example five-a-side, or similar, rather than an 11 v 11 game on a full size pitch) for one hour twice a week for six months
- the ‘advice group’ – where men were provided with standard advice from their GP about ways to lower blood pressure levels, such as increasing levels of exercise and eating a healthy diet
While your average Sunday morning game of amateur football is rarely an example of sporting excellence – more a case of the ‘the hapless and the hungover’ – the results were impressive.
Men in the football group had significantly lower blood pressure and increased aerobic fitness when compared to men in the advice group..
The main limitation of this study was its tiny sample size. Just 22 men received the football training, compared to 11 receiving the doctor advice. Also, all of the men were of white Danish ethnic origin.
This increases the possibility of chance results and severely limits how applicable the findings are to other groups, it also does not provide definitive evidence for the beneficial effect of football training on cardiovascular risk factors.
However, it would seem to suggest that regular physical activity, particualry one that imparts a feeling of enjoyment or achievement, is beneficial to overall health.
Where did the story come from?
The study was carried out by researchers from the University of Exeter (UK) and the University of Copenhagen (Denmark). It was funded by the FIFA Medical Assessment and Research Centre, the Danish Heart Foundation, the Danish Football Association and the Danish Sports Confederation. No conflicts of interest were declared by the authors.
The study was published in the journal Medicine and Science in Sports and Exercise.
The news coverage of this study was generally accurate, although it tended to overstate the importance of such a small study which only involved 33 middle-aged men.
What kind of research was this?
This was a randomised control trial investigating the fitness and health effects of medium-term football training for untrained middle-aged men with mild to moderate high blood pressure.
High blood pressure (also known as hypertension) is associated with an increased risk of developing cardiovascular diseases including stroke, coronary heart disease, and kidney failure.
It is also associated with a higher risk of dying from cardiovascular disease – diseases affecting the blood vessels or the heart – one of the biggest causes of premature death in the UK.
Physical activity has long been known to be effective at lowering blood pressure and reducing the risk of cardiovascular disease, but the exact relationship between exercise intensity and reduction in blood pressure had not been established. This study looked at the effect of football training as the authors thought it represented an “intense intermittent sporting activity” which previous research suggests can cause marked reductions in blood pressure.
What did the research involve?
The researchers recruited 33 males aged 31 to 54 years to the study. The men then had to be “untrained” meaning they had not performed regular physical training for at least one year. They also had to have a diagnosis of mild to moderate hypertension (blood pressure above 140/90 but below 160/110) but be otherwise healthy.
Following this process, the men would probably not be experiencing any noticeable symptoms, but their blood pressure levels would be a cause for concern as they could trigger a cardiovascular disease at some point in the future.
Men taking beta-blockers were excluded from the study (because these drugs lower heart rate), but other blood pressure medications, such as calcium channel blockers, were allowed.
The men were then randomised 2:1 to participate in a football training program or to receive doctor advice over the course of six months.
Men in the training group received two, one-hour supervised football training sessions each week for six months.
These were five-a-side, six-a-side, or seven-a-side matches, played on a 30-45m x 45-60m grass pitch (in comparison, a competitive football pitch must be between 45-90m x 90-120m).
Heart rate monitors were worn throughout the training sessions by all participants. Those in the control group received advice from a cardiologist on the favourable effects of a healthy lifestyle with thorough information about the recommended physical activity and diet requirements based on European guidelines for managing hypertension.
These participants were advised to take up regular exercise of moderate intensity, such as jogging or cycling.
For both groups, the researchers measured cardiovascular and fitness parameters before the interventions started and then three and six months after the interventions.
These measurements included:
- blood pressure
- resting heart rate
- peripheral arterial function (e.g. blood flow in their leg arteries)
- fat mass
- bone mineral content and density (bone strength)
- blood fat levels
- maximal oxygen uptake (the maximum amount of oxygen that an individual can make use of during intense or maximal exercise – measured using maximum volume of oxygen, VO2 max)
- exercise capacity during maximal and submaximal exercise (exercise capacity is measured by how long an individual can persist in performing a certain task, such as running on a treadmill)
The statistical analysis was appropriate and compared the men who received the football training programme to those that received a doctor’s advice only.
Intention to treat analysis was used (meaning that participants were analysed in the group to which they were assigned, regardless of whether or not they completed the trial).
What were the basic results?
Twenty two men received the football training (68% of whom were on medications for hypertension), compared to 11 men who received advice only (73% of whom were on medications for hypertension).
Over the six-month period, six people dropped out of the football training group and four from the doctor advice group. Two in the training group dropped out because they got injured playing football, and the remainder (from both groups) could not stick to the study protocol. All were included in the analysis.
In the football-training group, blood pressure decreased significantly over six months. The doctor advice group also reduced their blood pressure significantly during the same period, but the magnitude of the difference was smaller than the football group.
The football group decreased their average systolic blood pressure (the upper of the two figures of a blood pressure measurement, related to pressure in the arteries as the heart contracts) from 151±2 to 139±2mmHg (a decrease of 12mmHg). There was a similar decrease in their diastolic blood pressure (the lower of the two figures of a blood pressure measurement, related to pressure in the arteries as the heart fills with blood), from 92±2 to 84±1mmHg (a decrease of 8mmHg).
The doctor advice group decreased their average systolic blood pressure from 153±2 to 145±2mmHg (a decrease of 8mmHg) 96±2 to 93±2mmHg (a decrease of 3mmHg).
The maximum amount of oxygen a person could use during exercise – their maximal oxygen uptake – was significantly increased after 6 months in the football group (from 32.6±4.9 to 35.4±6.6ml per minute per kg) but not among those in the advice only group.
Similarly, following the football training intervention, the participants were able to use oxygen more efficiently during a cycling test compared to before the intervention, while no improvement was observed in the advice only group. Resting heart rate was also lowered significantly (by 8±5bpm) in the football group, with no change observed in the advice only group.
Finally, fat mass did not change significantly in either group after six months. However, on average, the football group lost approximately 2kg of fat mass over the six months, compared to 0.9kg in the advice only group.
How did the researchers interpret the results?
The researchers concluded that, “Six months of soccer [football] training improved aerobic fitness, reduced blood pressure and resulted in an array of other favourable effects on cardiovascular risk profile for untrained middle-aged hypertensive men. Soccer [football] training may, therefore, be a better non-pharmacological treatment for hypertensive men than traditional physician-guided advice.”
This very small study showed that six months football training of one hour, twice a week led to a host of favourable effects on cardiovascular measures for previously untrained middle aged men with mild to moderately raised blood pressure.
Furthermore, these benefits were greater in magnitude than those seen in an intervention based on giving advice only.
In many ways, this study tells us what we already know: that physical activity reduces blood pressure and has many beneficial effects on the cardiovascular system.
What this study adds, however, are some extra indicators of specific details of the physical activity (playing five, six or seven-a-side football, twice a week for approximately one hour) that can potentially bring about these beneficial effects in hypertensive men.
However, this study has some important limitations to consider.
First and foremost is the small sample size, it recruited just 33 men, of whom only 22 received the football training.
This small sample size makes it more likely that differences between the groups will not be found to be significant, or are significant by chance.
Similarly, we have to question how applicable the findings from these 22 men are to the rest of the population. Due to the strict inclusion criteria, the results are most applicable to 31-54 year old, mild-to-moderate hypertensive men who are “untrained” (meaning they had not performed regular physical training for at least one year) and who do not take beta-blockers (a common blood pressure medication).
Hence, the findings of this study may be less applicable to other people. Similarly, as every five-a-side football fan knows, goalies do a lot less physical activity than outfield players and so the effects may also be different for this unique group of players.
The effect of a full 11-a-side game was also not assessed, as men in this study played five-, six- or seven-a-side games on reduced size pitches.
Also, the study only included white Danish men. Rates of hypertension can vary significantly in different ethnic groups – with people of South Asian and Afro-Caribbean descent being particualry affected. Therefore, it is unclear whether football training would have a similar effect in these ethnic groups.
As this was a study looking at the effect of football training on cardiovascular risk factors (such as blood pressure), it did not directly study whether people receiving the football training were less likely to die of cardiovascular disease further down the line.
However, based on the wealth of previous research, it is a fair assumption that if training resulted in sustained benefits to cardiovascular health, then this would decrease their risk of death from related complications, though to what extent is unknown.
The researchers only looked at the physical advantages of playing football; they did not assess potential mental health, social or economic benefits which are likely to be numerous.
Physical activity is known to have many benefits aside from physical health, including stress relief, improving sleep and additional benefits from socialising.
This study alone does not provide definitive evidence for the beneficial effect of football training on cardiovascular risk factors, chiefly due to the small sample size; however it does provide a useful indication of the potential benefits that will need to be confirmed or refuted in larger studies.
Furthermore, it reinforces the public health message that regular physical activity has a wealth of benefits to health.
Finally, there is a large body of research that shows that people taking part in physical activities which they find personally enjoyable are more likely to persist with them.
So, if football is not the game for you, you may want to consider other activities, such as running, cycling or swimming.
Read more advice about getting started with exercise
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.