The average marathon running time was 5.4 hours for women and 4.5 hours for men - below average completion times.
So, not to say the obvious, doing your first marathon is pretty good for your health.
The researchers recruited runners with no significant medical history, ages 21 to 69, who had registered to take part in the 2016 and 2017 London marathons.
They examined the runners - almost half of whom were male - six months before they began training and within three weeks after completing the long-distance race.
On average, participants were 37 years old and 49% were male.
Marathon training reduced both brachial and aortic systolic blood pressures by 4 mm Hg - in line with the magnitude achievable on first-line antihypertensive drugs, the investigators reported. Tests included blood pressure measurements, measurements of aortic stiffness by cardiovascular magnetic resonance imaging and the determination of their vascular age. They had central blood pressure and aortic stiffness evaluated roughly 176 days before and 16 days after finishing the marathon.
The greatest benefits were seen in older, slower male marathon runners with higher baseline blood pressure, according to the study which published Monday in the Journal of the American College of Cardiology. So if you're not in great aortic shape to begin with, you might see greater benefits.
Researchers believe that adults with hypertension and stiffer arteries may have an even greater cardiovascular response to physical training. Their study underlines the significance of lifestyle moderation to retard the probabilities linked with aging particularly it seems to never be too late as revealed by the older slower runners.
"Our study shows it is possible to reverse the consequences of aging on our blood vessels with real-world exercise in just six months", said senior author Dr. Charlotte Manisty, a senior lecturer at University College London and a consultant cardiologist at the Barts Heart Centre and University College Hospitals.
"These benefits were observed in healthy individuals in general over a wide age range and their marathon times suggest exercise training attainable in novice participants".
You don't have to force yourself to do a marathon to improve your health, of course.
Any exercise you feel will have benefits.
Our Associate Medical Director, Professor Metin Avkiran also gave his thoughts: "The benefits of exercise are undeniable".
'Staying active reduces the risk of having a heart attack or stroke and reduces the chances of premature death. Every person included in the study had health checks before they started their marathon training, which lasted for six months.
'Aim for at least 150 minutes of moderate intensity exercise every week, or 75 minutes of vigorous exercise. In addition, training for marathons usually involves various concomitant approaches such as better sleep and dietary patterns, and in some instances, over-the-counter supplements, that may confound or interact with exercise training per se.