# Exercise as it relates to Disease/Exercise and Hypertension: What is the most beneficial exercise for reducing hypertension
### What is hypertension?

Blood pressure can be described as the maximum pressure of blood on the artery walls when the heart contracts (systolic) and minimum pressure when relaxed (diastolic) measured in milliliters of mercury (mmHg). Normal blood pressure is less than 120/80mmHg. Hypertension simply means high blood pressure of >140/90mmHg and is the result of a chronic increase in pressure on the arterial walls. Many lifestyle factors contributing to high blood pressure include:
* Diet: high salt intake, low potassium intakes and inadequate intakes of fruit and vegetables
* Alcohol: excessive amounts (greater than 3 drinks/day)
* Physical inactivity
* Weight: being overweight or obese
* Ageing: More likely to develop high blood pressure with increasing age
* Smoking: through decreased baroreflex function and increase sympathetic drive
* Stress
While hypertension itself is caused by multiple factors it is also a major risk factor for cardiovascular (CV) disease and chronic kidney disease (CKD). As a result of this there is an increased risk of CV mortality from strokes and heart disease.

### Prevalence

In the most recent Australian health survey data (2011–2012) approximately 3.1 million of Australians aged 18 years and older had high blood pressure and at 21.5% that is almost a quarter of the population. Both men (23.6%) and the elderly at 65 years and older (42.5%) were more likely to have measured high blood pressure than women (19.5%) and those aged 18–24 years (only 6%).
World Health Organisation (WHO): A global brief on hypertension, showed that in 2008 cardiovascular disease accounted for 7.1 billion deaths per year and of this 9.4 million were from hypertension as a result of strokes or heart disease.
World Health Organisationː World health statistics 2012 found that of the risk factors attributable to noncommunicable deaths, high blood pressure is the leading cause (13%) followed by tobacco use, raised blood glucose, physical inactivity and being overweight or obese, highlighting the global importance of reducing blood pressure.

### Classifications

According to the National Heart Foundation of Australia: Guide to management of Hypertension 2008.
| Diagnostic Category | Systolic BP (mmHg) | Diastolic BP (mmHg) |
| Normal | <120 | <80 |
| Normal-High | 120-139 | 80-89 |
| Grade 1 (mild) Hypertension | 140-159 | 90-99 |
| Grade 2 (moderate) Hypertension | 160-179 | 100-109 |
| Grade 3 (severe) Hypertension | ≥180 | ≥110 |
| Isolated systolic Hypertension | ≥140 | <90 |
| Isolated systolic Hypertension with widened pulse pressure | ≥160 | ≤ 70 |

## Effects of exercise on hypertension
### Aerobic exercise

Regular aerobic exercise has been shown to decrease blood pressure even with relatively low intensities of 50% VO2max, with decreases of 6-7mmHg in both systolic and diastolic blood pressure. Cardiac output remained the same due to a decrease in heart rate and an increase in strove volume. Decreases of 5mmHg in blood pressure has significant benefits in decreasing stroke mortality by 14% and decreasing coronary heart disease by 9%.

### Resistance exercise

According to the American College of Sports Medicine and other studies, progressive resistance training at a moderate intensity has been shown to have a small but crucial effect on reducing blood pressure by around 3mmHg for both systolic and diastolic.
Reduced blood pressure effects from both forms of exercise were greater in hypertensive than non-hypertensive subjects. Both aerobic and resistance training also had beneficial effects on other CV risk factors including: increasing VO2 peak, decreases in body fat (abdominal and visceral), plasma triglycerides, glucose and insulin

## Recommendations
### Considerations for exercise

Australia's position statement for exercise and hypertension
* Elderly with hypertension: Medical evaluation prior to exercise, longer cool down period and adequate fluid intake
* Supervision: Exercise physiologist should regularly check both resting and exercising blood pressure of hypertensive patients
* Medications: Effects on exercise, such as beta blockers (impair thermoregulation and reduce HR) and Diuretics (hydration)
* Postpone exercise if resting blood pressure is >180/110mmHg
* Cessation of exerciseː with hypertensive blood pressure response of >250/115mmHg and hypotensive responses due to an inadequate rise of systolic blood pressure dropping below >10mmHg of resting systolic blood pressure. As well as any feelings of chests pains when exercising

### Aerobic, Resistance or both?

A combination of both an aerobic and resistance exercise program is most beneficial and recommended to reduce blood pressure in those with hypertension. Frequency, duration, and type of exercise program will differ with individuals. Recommendations by the American College of Sports Medicine:
* Aerobic exercise:
** Walking or Cycling at moderate intensity (40-60% VO2) for 30mins, 5days/week OR
** Jogging or running at vigorous intensity (60-84% VO2) for 20mins, 3days/week
* Resistance exercise:
** Progressive weight training, with 8-12 repetitions, 1 set of 8-10 exercises, for 2 (or more) non-consecutive days/week

## Helpful Resources

* http://www.heartfoundation.org.au/SiteCollectionDocuments/HypertensionGuidelines2008to2010Update.pdf
* WHOː A global brief hypertension http://apps.who.int/iris/bitstream/10665/79059/1/WHO_DCO_WHD_2013.2_eng.pdf?ua=1
* Australia's Position statement on exercise and hypertension (seen in reference list)

## References

* 1 2 3 4 5 6 7 Sharman, JE & Stowasser, M. (2009), 'Australian Association for Exercise and Sports Science Position Statement on Exercise and Hypertension', Journal of Science and Medicine in Sport, vol. 12 no. 2, pp. 252-257.
* ↑ National Heart Foundation of Australia, (2008) Your Blood Pressure [online]. Available from: http://www.heartfoundation.org.au/SiteCollectionDocuments/A_Hypert_Guidelines2008_ISC_YourBloodPressure.pdf
* 1 2 3 Giles, TD. (2008), Assessment of Global Risk: A Foundation for a New, Better Definition of Hypertension [online], The journal of clinical hypertension, vol. 8 pp. 5; 5-14; 14.
* 1 2 3 4 Geleijnse, JM. et al. (2004), Impact of dietary and lifestyle factors on the prevalence of hypertension in Western populations [online], European journal of public health, vol. 14 no. 3, pp. 235-239.
* 1 2 3 Australian Bureau of Statistics, (2012) Australian Health Survey: First Results 2011-2012 [online]. Available from: http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/242991D3B407CE6ACA257AA30014C138?opendocument
* ↑ Narkiewicz, K. et al. (2005), Is smoking a causative factor of hypertension? [online], Taylor & Francis Ltd.
* ↑ Grossman, E. (2008), Does increased oxidative stress cause hypertension? [online], Diabetes care, vol. 31 Suppl 2, pp. S185-9.
* 1 2 National Heart Foundation of Australia. (2008) (National Blood Pressure and Vascular Disease Advisory Committee). Guide to management of hypertension [online]. Updated December 2010. Available from: http://www.heartfoundation.org.au/SiteCollectionDocuments/HypertensionGuidelines2008to2010Update.pdf
* ↑ WHO. (2013) A global brief on hypertension: Silent killer, global public health crisis [online]. Available from: http://www.who.int/cardiovascular_diseases/publications/global_brief_hypertension/en/
* ↑ WHO. (2012) World health statistics 2012 [online]. Available from: http://www.who.int/gho/publications/world_health_statistics/2012/en/
* 1 2 Fagard, R. (2006), Exercise is good for your blood pressure: effects of endurance training and resistance training [online], Clinical and Experimental Pharmacology and Physiology, vol. 33 no. 9, pp. 853-856.
* 1 2 Cornelissen, VA. & Fagard, RH. (2005), Effects of endurance training on blood pressure, blood pressure-regulating mechanisms, and cardiovascular risk factors [online], Hypertension, vol. 46 no. 4, pp. 667-675.
* 1 2 Cornelissen, VA. et at. (2011), Impact of resistance training on blood pressure and other cardiovascular risk factors: a meta-analysis of randomized, controlled trials [online], Hypertension, vol. 58 no. 5, pp. 950-958.