The pattern of society is well established, do nothing, get sick, take meds and repeat. It’s self destructive. Those of us who make a living studying the way physical activity interacts with the body’s physiology see the underbelly of such behaviour. As a result, we preach prevention, active therapy and the art of consistent movement as a detour around side-effect laden pharmaceutical interventions.
It often takes an innocent comment to remind us of the true tangible benefits of physical activity. The commenter: a 40-something female client who has been battling with increased blood pressure stemming from a high octane work schedule, desk jobs and parenthood who has been on medication for a few years. After just a few sessions at the gym, she sent me a text proclaiming her joy at seeing her blood pressure drop without medication. For any busy workaholic, seeing how the body responds positively to even a little bit of exercise can prove the difference between long term adherence and actively choosing sedentarity.
Blood pressure is the measure of the amount of force applied to arterial walls during blood flow. Consistently elevated blood pressure (hypertension) strongly correlates with increased risk of heart disease. Blood pressure is measured in millimetres of mercury (mmHg) and expressed as
Systolic Blood Pressure (during heart beat)
Diastolic Blood Pressure (in between heart beats)
There are various “normal values” for blood pressure, the below chart is one common interpretation of blood pressure results from the American Heart Association. There are various conditions that affect blood pressure so get your doctor’s opinion as well as the world wide web’s.
- Blood pressure can fluctuate greatly throughout the day, one high blood pressure reading is not usually enough to diagnose hypertension.
- Blood pressure readings can be falsely elevated in new & uncomfortable environments.
- Blood pressure readings vary based on seated, standing or lying positions.
Hypertension (high blood pressure)
Consistently high blood pressure is a risk factor for:
- Heart Failure
- Kidney Failure
There are various factors that affect the blood pressure
- Volume of fluid (blood).
- Resistance – mainly in the peripheral arteries. Plaque build up (atherosclerosis) is the most common type of resistance, as resistance increases, blood pressure increases.
- Viscosity – thickness of the blood.
The role of exercise in blood pressure physiology is thought to work by decreasing peripheral arterial resistance. Like any bodily system, it improves with use. If the muscles are never demanding increased blood flow they remain stagnant for prolonged periods of time and do not develop into efficient systems. Increased exercise and activity helps decrease peripheral resistance by improving the blood flow to the musculature and therefore reducing the resistance to blood flow and subsequently decreasing blood pressure.
Acute v Chronic Exercise
Blood pressure has been shown to positively respond to exercise immediately following a bout of exercise. This is known as post-exercise hypotension. Acute exercise can create some short term benefits in blood pressure management but it requires transition to chronic exercise routine to gain more long term benefits. Chronic exercise can be viewed as a series of acute benefits that compound individual bouts of exercise upon one another, leading to long term reductions in blood pressure.
There are a variety of studies that have set out to identify the mechanisms relating to the immediate drop in blood pressure following an acute bout of exercise. The actual mechanisms are thought to vary between trained and untrained people.
On average, “following acute exercise, the average ambulatory BP taken over 24 hours is reduced on average by 3.2 and 1.8 mm Hg for systolic and diastolic BP, respectively.” (1)
Evidence supporting the positive impact of exercise on blood pressure is abundant. Below are two review studies that have undertaken the task of reviewing the research on the topic of exercise and blood pressure response.
1. Exercise characteristics and the blood pressure response to dynamic physical training. – R.H. Fagard (2001) (2)
A 2001 review study by Belgian researcher Robert Fagard gathered and analysed data from 45 studies to ascertain whether the is enough supportive evidence to show the practical impact of exercise and physical activity on blood pressure.
The review concluded that: (note: normotensive = normal blood pressure; hypertensive = high blood pressure)
- Changes: “the blood pressure lowering effect is small but significant in normotensive subjects, averaging approximately 3/2 mm Hg…the net effect is more pronounced in hypertensives who benefit from an average blood pressure reduction of 7/6 mm Hg.”
- Intensity: The reviewed studies averaged an intensity equal to 65% of VO2 Max.
- Frequency: “Training from 3-5 times per week during 30–60 min per session reduces blood pressure, particularly in hypertensives.”
2. The Role of Exercise Training in the Treatment of Hypertension. – J.M. Hagberg, J. Park and M.D. Brown (2000)(3)
A 2000 review by Hagberg, Park and Brown reviewed numerous studies relating to the blood pressure response to exercise. They explored many of the different factors that can predict and result in blood pressure responses.
The review (3) concluded that:
- 76%, decreased systolic BP significantly with exercise training
- 81%, reduced diastolic BP significantly with exercise training.
- “The consensus is that systolic BP in hypertension patients is generally reduced for a number of hours following an acute bout of exercise.”
- “These results continue to indicate that low to moderate intensity endurance exercise training is just as, if not more, efficacious as higher intensity training for reducing BP in hypertensive individuals.”
Table 3 (above) shows that the largest improvement in blood pressure response occurs in the early stages following exercise intervention. However, chronic exercise adherence helps maintain the blood pressure drop.
- If you suffer from chronic hypertension, get your blood pressure checked prior to exercise. The upper limit we use in my clinic is no exercise if someone’s blood pressure is systolic >180 mm Hg or diastolic > 110 mm Hg
- Don’t hold your breath throughout exercise
- Be conservative – if you are feeling dizzy, nauseous, short of breath or feeling chest pains don’t power through. Play it safe when it comes to stress on the heart.
Type of Exercise
- Aerobic exercise is the most direct way of positively affecting blood pressure. Aerobic exercise aims to improve the heart as a muscle.
- 30-60 minutes of low-moderate intensity (40-60% VO2 Max) aerobic exercise 3-5 days/week.
- Exercises such as: walking, swimming, cycling
(1) Pescatello, L., & Kulikowich, J. (2001). The aftereffects of dynamic exercise on ambulatory blood pressure. Medicine and Science in Sports and Exercise, 33(11), 1855-1861.
(2) Fagard, R.H. (2001). Exercise Characteristics And The Blood Pressure Response To Dynamic Physical Training. Medicine and Science in Sports and Exercise, S484-S492.
(3) Hagberg, J., Park, J., & Brown, M. (2000). The Role Of Exercise Training In The Treatment Of Hypertension: An Update. Sports Medicine, 30(3), 193-206.
(4) Hamer M. (2006). The Anti-Hypertensive Effects of Exercise – Integrating Acute and Chronic Mechanisms. Journal of Sports Medicine, 36(2), 109–116.