"Exercising regularly 'can keep heart and arteries young'," BBC News reports.
Researchers recruited 102 older adults with an average age of 70 to a study looking at the relationship between exercise history and the health of their main arteries. All participants were considered healthy, and reported consistent exercise patterns over the last 25 years.
The researchers took various measures of blood flow and stiffness of the arteries. Excessive stiffness of the arteries can be associated with high blood pressure and atherosclerosis – a potentially serious condition where fatty clots build up in the arteries, which can then block the supply of blood to the heart or brain, triggering a heart attack or stroke.
People who reported doing the highest frequency of exercise (6 to 7 sessions a week) had the best measures of health for the main artery leaving their heart (the aorta). All people who did 2 or more sessions of exercise a week had healthier measures for the carotid arteries supplying their brain than people who did little or no exercise.
Unfortunately, this study alone doesn't tell us a great deal. While these measures are indications of arterial health, we don't know whether this makes any difference to risk of developing heart disease or stroke. It's a small sample and different findings may be observed in other samples, such as people who have health problems. Also, estimated amounts of exercise people have done over the years will never be entirely accurate.
However, it supports the recommendations that regular exercise is good for health and what is good for the heart is often also good for the brain.
The study was carried out by researchers from several institutions in Texas including the University of Texas, the John Peter Smith Health Network, and the TCU and UNTHSC School of Medicine. It was funded by a US National Institutes of Health grant, and published in the peer-reviewed Journal of Physiology.
BBC News covered the research in brief. The article quoted one of the researchers as suggesting that it might be possible to "turn back time on older hearts and blood vessels," but this is speculative and not related to the research that was carried out. The BBC's coverage also gave the impression the results were clearer cut and more meaningful than they actually were.
The Mail Online's coverage of the study was a little more in-depth than the BBC's, but again, the limitations of the study were not discussed.
This was a cross-sectional study in which researchers identified a group of people at a single point in time. They measured their arterial health and looked into their previous exercise experience.
However, cross-sectional studies can never tell us cause and effect. We don't know that the person's long-term past exposure of exercise is directly responsible for their current health status as many other factors may be involved.
One benefit of this study is that the participants were part of a larger cohort study that collected the information about how often people exercised over time. This is better than asking people to recall their exercise history on only one occasion.
Nonetheless, the classification of exercise purely by frequency and not by type or intensity limits how much the results can be interpreted. Also, it might have been useful to measure arterial stiffness at several points over time to see how it changed with age and the number of years of exercise.
The research included people who were already involved in a long-term study, the Cooper Centre Longitudinal Study. Although the cohort involved more than 80,000 people, the researchers only recruited a group of 102 people to this study, who were considered healthy and had reported a consistent exercise pattern over the past 25 years.
People were split into groups according to their exercise habits:
Exercise was defined as aerobic exercise lasting at least 30 minutes per session.
People recruited to this study had a range of measurements taken, including body mass index (BMI), medical history, questions about smoking habits, and assessments for various health conditions. Regular smokers and those with obesity, high blood pressure, diabetes, heart disease, heart rhythm or valve problems or respiratory disease were excluded. The researchers also gave participants various heart tests and excluded those where the results suggested they had blocked arteries or their artery walls were not moving normally.
For the people who remained, the researchers then used a type of ultrasound scan to assess the health of their main arteries.
The researchers looked at various measures of stiffness and blood flow in the main artery coming from the heart (the aorta) and other arteries supplying the limbs. They generally found that measures were better in people who were committed or competitive exercisers than in people who were sedentary or casual exercisers.
Looking at the health of the carotid arteries (which supply the brain), people in the sedentary group had stiffer arteries than the casual, committed and competitive exercise groups.
The researchers noted that their findings were consistent with previous research, in particular that 4 to 5 sessions of exercise a week was likely to be beneficial to the health of the arteries. They noted their study did not take into account other factors that may have influenced artery health such as diet, overall physical activity outside of exercise (such as having a very active job), and various socioeconomic factors.
It's difficult to conclude a great deal from this study or know how meaningful the results are.
The study can't prove cause and effect and say that arterial health is directly a result of exercise frequency. Many other unmeasured factors might influence arterial stiffness, such as diet, alcohol or other health conditions.
The study included only a small sample. This may result in chance findings that are not repeated in other samples and can't be applied to the general population. This includes people of different cultures and ethnicities and those with existing health conditions (who were excluded from this study).
This study also only included people who had a consistent exercise habit throughout their lives. This helped the researchers try and apply their findings to specific exercise patterns, but it's not very representative of real life. Many people have a varied exercise habit over their lives due to changes in health and circumstances.
The study also doesn't tell us anything about the intensity of exercise – only the number of sessions a week – so we can't even know if the findings can be applied to a certain level of exercise.
Although arterial stiffness is a relevant measure in looking at heart and artery health, this study did not go on to look at whether this had any direct effect on people's overall health. While the researchers found trends in arterial health according to exercise, we cannot tell from this study alone whether these differences are enough to prevent disease.
That said, there are undoubted benefits of exercise. As one public health expert said: "if exercise were a pill, it would be one of the most cost-effective drugs ever invented".