Guidelines: FAQs


Why are there two different sets of physical activity recommendations?

Prescription for Exercise (P4E) gives access to the UK physical activity guidelines (2011) and the P4E condition specific recommendations. The UK Physical activity guidelines, published by the Department of Health, cover early years; children and young people; adults; and older adults. Individual physical and mental capabilities need to be considered when interpreting the guidelines. The P4E condition specific recommendations are based on these guidelines but have been produced for adults with specific chronic conditions who have been inactive for a long time. The P4E recommendations provide disease specific health benefits and suggestions for activity which include safety considerations.

Why are the physical activity recommendations termed ‘health-enhancing’?

The recommendations focus on reducing risk of chronic disease and providing health benefits for those with long term conditions. The recommendation therefore focus on health related fitness rather than performance-related fitness.

Why do the ‘UK Physical activity guidelines’ recommend two levels of intensity?

To meet the recommended guidelines, adults can do either moderate-intensity activity or vigorous-intensity activity or a combination of both. It takes less time to get the same benefit from vigorous-intensity activities than moderate intensity activities. Generally, 2 minutes of moderate intensity activity is equal to 1 minute of vigorous activity. Health benefits depend on total weekly energy expenditure due to physical activity. Generally, adults should achieve 500-1,000 MET-minutes or more per week to gain substantial health benefits.* The aim for better health is to expend enough energy and whether that is through moderate or vigorous levels of activity does not matter a great deal.

*MET or metabolic equivalent is a unit describing energy expenditure of a specific activity. A MET is the ratio of the rate of energy expended during activity to the rate expended at rest. A 4 MET activity expends 4 times the energy used by the body at rest. Therefore a 4 MET activity done for 30 minutes is 120 MET-minutes (4 x30=120).

Why do the ‘Condition Specific guidelines’ suggest relative moderate intensity activity and not vigorous ones?

The P4E ‘Condition Specific guidelines’ focus on patients with, or at risk of, chronic conditions who have been inactive for a long time. In general, relative moderate intensity activities in these patients are safe and beneficial 1. Those patients who wish to carry out vigorous intensity activity may need exercise grading testing 2. Equally, people with long term conditions who do regular activity, which may already include vigorous activity, should be encouraged to carry on doing so. It must be remembered that the key for health related fitness is to obtain the total weekly energy expenditure rather than reaching high intensity activities. Generally, 2 minutes of moderate intensity activity gives the same amount of health benefits to 1 minute of vigorous activity. Return to top

Why does the ‘Condition Specific recommendation’ suggest relative moderate intensity?

Intensity of aerobic physical activity may be defined in absolute or relative terms. The relative intensity of aerobic activity is related to a person’s level of cardiorespiratory fitness. A person doing relative moderate-intensity aerobic activity can talk, but not sing, during the activity. The P4E recommendations, which focus on people with chronic disease who have been inactive for a long time, use relative intensity as it tracks the level of effort required to do an activity. Less fit people generally require higher level of effort than fitter people.

Is physical activity safe?

Scientific evidence strongly shows that the health benefits of physical activity far outweigh the risks. The P4E condition specific recommendations empower people to carry out physical activity safely. Most people are not likely to be injured when doing moderate-intensity activities in amounts recommended by the UK Physical activity guidelines. People must introduce new activity within their capabilities and progress gradually with experience. The most common injuries are musculoskeletal ones, and others can include dehydration or overheating. On rare occasions, people have heart attacks during activity. The absolute risk of sudden death during and up to 30 minutes after vigorous activity is extremely low, even in individuals with cardiac disease (1 sudden death per 1.51 million episodes of physical exertion) 3. The Getting started and P4E condition specific recommendations provide advice to help people do physical activity safely. Maintaining physical activity reduces overall injury risk during activity and it appears less likely to have non-activity related injury as well as increasing your overall health.

When do patients need a medical consultation before increasing activity levels?

The value of a medical consultation for people wanting to increase physical activity levels is not established. People without chronic conditions who do not have symptoms (such as chest pain, dizziness or joint pain) do not need to consult. Inactive people who gradually progress over time to moderate intensity levels have no known risk of sudden cardiac death and very low risk of musculoskeletal injury 4. A healthy person who is regularly active can gradually increase to vigorous intensity activity without needing to consult.

People with chronic conditions typically find that moderate intensity activity is safe and beneficial1. For these patients, a medical consulation, checking for current disease status and addressing safety precautions (which are found on each disease specific recommendation) are recommended to prevent injury and importantly to reinforce the benefits of physical activity in the management of chronic disease. A medical consultation is appropriate for people with chronic conditions who wish to embark on vigorous activity because the risks are higher than the risks of moderate-intensity ones. These patients should be considered for exercise testing before beginning vigorous activities 5. Disease status, age, prior experience of activity and current activity levels are important when considering the safety of patients with chronic conditions wanting to do vigorous intensity activity.


  1. BHF (2008) Physical activity to reduce cardiovascular risk, Fact file 5. London: British Heart Foundation (BHF).
  2. Department of Health and Human Services (2008) Physical Activity Guidelines Advisory Committee Report, Washington, DC: US Department of Health and Human Services)
  3. BHF (2008) Physical activity to reduce cardiovascular risk, Fact file 5. London: British Heart Foundation (BHF).
  4. Department of Health and Human Services (2008) Physical Activity Guidelines Advisory Committee Report, Washington, DC: US Department of Health and Human Services)
  5. Exercise and Acute Cardiovascular Events: Placing the Risks into Perspective. A joint position statement by American College of Sports Medicine and American Heart Association. Medicine & Science in Sports & Exercise: May 2007 – Volume 39 (5 ), pp 886-897

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