Vigorous Exercise can Lower Heart Disease Risk in Teens

Highlights:

• A decrease in blood pressure below resting values known as post-exercise hypotension was observed in teenagers who underwent high-intensity exercise
• The fall in blood pressure lasted up to one hour post-exercise and was not dependent on the stretch of the carotid artery and the brain control of the heartbeat.
• Vigorous exercise at a young age could have heart benefits later in life.

Teenagers who participate in high-intensity exercise have lower blood pressure and can lower the risk of developing heart disease later in life, according to new research conducted by a research team at the Children's Health & Exercise Research Centre, University of Exeter and published in Experimental Physiology. Research suggests that teenage years are when heart diseases start to develop. Doing high-intensity exercise during this phase of life makes potential differences in heart health benefits says the current study. The authors say this could lead to a lower risk of developing heart disease later in life, although this fact requires confirmation with further research.

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Details of the Study

The researchers recruited healthy teenage males (12-15 years old) who were asked to undergo four tests conducted at separate occasions across three weeks.

1. During the first visit, participants performed an exercise test to calculate the intensity with which they could exercise.

After this first visit, all participants went through three experimental conditions on separate days in a random order; they were asked to perform

2.Vigorous intensity exercise (8 bouts of one-minute's worth of running at a vigorous intensity)

3.Moderate intensity exercise (running at moderate intensity/jogging)

4. No exercise (control)

Parameters that were monitored and measured were

• Blood pressure at every heartbeat before and up to one-hour after the exercise
• Ultrasound images of the carotid artery, the main blood vessels that supply the head and neck with oxygenated blood (to determine the 'stretch' of the artery and how this impacts the control of blood pressure following exercise)

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Results of the Study

• In the vigorous intensity exercise (equal to running close to the maximum heart rate) group, post-exercise hypotension was observed in the hours following exercise; i.e., the blood pressure decreased below resting values; the same effect was not observed following moderate intensity exercise where blood pressure was restored just twenty minutes after exercise indicating that the vigorous intensity exercise was instrumental in causing post-exercise hypotension lasting up to one-hour.
• The stretch of the carotid artery and the brain control of the heartbeat which monitor and adjust blood pressure were similar between the two exercise intensity groups at one-hour following exercise.
• These findings indicate that exercise intensity causes the change in blood pressure by altering other mechanisms of adjustments, one-hour following the completion of the exercise in healthy teenagers.

This is the first study that shows the dependency of post-exercise hypotension on exercise intensity in healthy 12-15-year-olds. The decrease in blood pressure of healthy teenagers could have a long-term clinical importance when it is translated to those who have high blood pressure. Similarly, reducing blood pressure through exercise could lead to better blood pressure control, particularly when young people face stressful situations.

However, the shortcomings of the study were

• All measurements were taken non-invasively because the study group consisted of teenagers; this may have reduced accuracy in comparison to more invasive drug-infusion methods.
• The research involved only boys, so the findings cannot be extrapolated to girls.
• The observed blood pressure reduction was measured only up to one-hour after a single bout of exercise.

The authors are planning to expand these initial findings to children, and teenagers with hypertension and other conditions such as obesity and low levels of fitness that increase heart disease risk.

Similarly, the research team also wish to investigate whether the decrease in blood pressure causes lowering of vessel reactivity to stressful situations. Finally, the effects of exercise training on blood pressure control following exercise in teenagers remain to be seen.

Ricardo Oliveira, a Brazilian Ph.D student funded through the Science without Borders Ph.D scheme who led the research, enjoyed testing (and educating) the participants: "The best part of the research was the involvement and dedication of the participants, who we always find are better research participants than adults! All were disappointed that the project came to an end and they reported to have enjoyed visiting the university facilities, participating in a scientific study and learning new information about their heart, blood vessels and how the cardiovascular system responds to exercise.”

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Blood Pressure

An optimal blood pressure reading is considered to be under 120/80mmHg. If the blood pressure is persistently higher than normal then a person is said to have high blood pressure.

If the blood pressure has been high over a long time it is considered one of the main risk factors for heart disease. The chances of having persistently high blood pressure increases with age.

To keep blood pressure under control, aerobic exercise (in which your heart beats harder and you use more oxygen than usual), such as brisk walking, is very important. Moderate-intensity aerobic exercise at least 2 and a half hours per week, or vigorous-intensity aerobic exercise for 1 hour and 15 minutes per week is highly recommended to lower blood pressure.

References:

1. Ricardo Oliveira  Alan R. Barker  Florian Debras  Alexandra O'Doherty  Craig A. Williams "Mechanisms of blood pressure control following acute exercise in adolescents: Effects of exercise intensity on haemodynamics and baroreflex sensitivity" (2018) Experimental Physiology https://doi.org/10.1113/EP086999
2. Blood pressure - (https://www.heartfoundation.org.au/your-heart/know-your-risks/blood-pressure)
3. How to Prevent High Blood Pressure - (https://medlineplus.gov/howtopreventhighbloodpressure.html)

Source-Medindia