weight reduction is best achieved by a combination of dietary change and increased physical activity
increased physical activity carries significant benefits for cardiovascular performance, blood pressure, blood lipids and glucose metabolism
to achieve long-term increases in physical activity, these will need to be incorporated into everyday life, e.g cycling or brisk walking - a suitable duration would be 20-30 minutes per day
increased physical activity results in only modest changes in weight, averaging 0.5 to 1kg reduction each month (1) - walking an additional 2,000 steps per day increases energy expenditure by 100 calories
increased physical activity should therefore be combined with calorie-restricted diet in order to achieve significant weight loss
physical activity tends to become easier with time - this promotes a virtuous cycle in which physical activity increases further as the activity becomes easier to undertake
people who persist with regular physical activity are more likely to maintain their weight loss
NICE have stated
with respect to exercise in adults (2):
adults should be encouraged to increase their physical activity even if they do not lose weight as a result, because of the other health benefits physical activity can bring, such as reduced risk of type 2 diabetes and cardiovascular disease. Adults should be encouraged to do at least 30 minutes of at least moderate-intensity physical activity on 5 or more days a week. The activity can be in one session or several lasting 10 minutes or more
to prevent obesity, most people should be advised they may need to do 45-60 minutes of moderate-intensity activity a day, particularly if they do not reduce their energy intake. People who have been obese and have lost weight should be advised they may need to do 60-90 minutes of activity a day to avoid regaining weight
weight loss should be a maximum of 0.5-1 kg/week
management of obesity
only consider drug treatment for obesity if dietary, psychological and exercise interventions have been tried and failed
consider surgery for people with severe obesity if BMI 40 or more or 35-40 with significant disease, all non-surgical interventions should have been tried for at least 6 months
consider surgery as a first line option for adults with a BMI of more than 50 kg/m2
adults should be encouraged to build up to the recommended levels for weight maintenance, using a managed approach with agreed goals. Recommended types of physical activity include:
activities that can be incorporated into everyday life, such as brisk walking, gardening or cycling
supervised exercise programmes
other activities, such as swimming, aiming to walk a certain number of steps each day, or stair climbing
any activity should take into account the person's current physical fitness and ability
people should also be encouraged to reduce the amount of time they spend inactive, such as watching television or using a computer
with respect to children (2):
children should be encouraged to do at least 60 minutes of at least moderate activity each day. The activity can be in one session or several lasting 10 minutes or more
children who are already overweight may need to do more than 60 minutes' activity
children should be encouraged to reduce sedentary behaviours, such as sitting watching television, using a computer or playing video games
only consider drug treatment for obesity if dietary, psychological and exercise interventions have been tried and failed for at least 6 months
if drug treatment is considered appropriate this should be commenced by a specialist as part of a multi-disciplinary team
surgery should only be considered in exceptional circumstances
the World Health Organisation (WHO) advises that:
children between 5-17 years of age should be engaged in at least 60 minutes of moderate to vigorous exercise on a daily basis with the majority of this being aerobic in nature (3)
NHS choices suggest that children under 5 should be encouraged to be active for at least 180 minutes daily (4)
regular physical activity has important effects on the distribution of body fat, favouring reduced adiposity
the redistribution of body fat associated with regular exercise reduces the risk of both coronary heart disease, the metabolic syndrome and type 2 diabetes occurring
other cardiovascular effects of regular physical activity include (1):
improved
cardiac contractility
stroke volume
electrical stability
endothelial function
collateral circulation
reduced
blood pressure
platelet aggregation
plasminogen activator inhibitor 1
plasma-fibrinogen
C- reactive protein
triglycerides
mortality
increased
fibrinolysis
HDL-cholesterol
lipoprotein lipase
insulin sensitivity
Contributors May 2012:
Dr Alethea Beck General Practitioner, Scotland
Dr Andrew Murray Sports and Exercise Medicine registrar, Scotland
Reference:
British Heart Foundation (1/2005). Factfile - Obesity: physical activity
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