If you want to keep as healthy as possible there are two mantras we always hear: “eat a balanced diet” and “get regular exercise”. Not exactly information you can put into practice unless you are given more detail.
We talk quite a bit about what a ‘good diet’ means. So what does ‘regular exercise” entail?
For some years, exercise was promulgated as part of the energy-in (food) and energy-out (exercise) equation aimed at keeping our weight in a healthy range. Indeed, there were often diagrams showing how far you had to walk or run if you ate something like a chocolate bar or apple.
However, research has shown that exercise is more than ‘energy expended’. It plays a role across a number of physical conditions – and has also shown to have mental benefits.
According to the US Centers for Disease Control and Prevention, inactivity increases the risk of early death, type 2 diabetes, heart disease, stroke, osteoporosis, depression, and some cancers. 
In November 2018, the US Department of Health and Human Services released its second edition of the ‘Physical Activity Guidelines for Americans’ to provide evidence-based recommendations for children and adults.  Included in it is new evidence about specific health benefits of exercise and updated guidelines for different age groups as well as adults and those with chronic diseases or disabilities.
New Zealand’s Ministry of Health also has a wide range of recommendations around exercise for different age groups. 
Here are some of the key highlights from these sources:
Are encouraged to ‘exercise’ from just ‘moving more’ to more than 5 hours of moderate-intensity aerobic activity a week.
Level 1: the idea is to simply move more frequently and sit less. The reason for this is that new evidence shows a strong relationship between being highly sedentary and an increased risk of heart disease, high blood pressure, and deaths from all causes. It is seen, therefore, that all types of physical activity/movement can help offset these risks. Being a couch potato is a no-no
Level 2: increased health benefits come from the recommendation to do at least 150 to 300 minutes (2 ½ to 5 hours) a week of moderate-intensity aerobic activity, such as brisk walking or fast dancing. At least two days a week should also include muscle-strengthening activities, such as lifting weights or bodyweight exercises – push-ups, lunges, and squats. Ideally, they should be spread through the week. It is far better to exercise for 45 minutes every other day at a moderate-to-vigorous level than to sit around during the week and rush out to do 1 ½ hours on Saturday and Sunday.
Level 3: to continue to improve health benefits even more, then exercising over and above level 2 – without being extreme – is recommended.
A key recommendation is to add flexibility and balance training e.g, tai chi or yoga. This may help prevent falls and accidents. Nevertheless, younger people will also benefit from these disciplines
Adults with chronic conditions and disabilities
Those who are able to exercise are very much encouraged to do so. However, the types and amounts of activity that are appropriate needs to be discussed with experts and will depend on the disability.
Children 3-5 years old
Should be encouraged to have physical activity throughout the day for growth and development. Active play for at least three hours a day should be encouraged.
Children 6 and up to 17
Should have at least one hour a day of moderate to vigorous activity with a combination of aerobic (walking, running, or anything that increases the heart rate) and strength movements to build muscles and bones (climbing on playground equipment or rock climbing walls, playing basketball, and jumping rope). If one hour a day can be achieved, more specific goals may be created, such as including three days a week of vigorous activity and three days of strengthening activities (within the one hour).
For everyone starting from a low level of exercise the idea is to build up over time – to “start low and go slow” with lower intensity activities and then gradually increase how often and how long the activities are performed.
Research shows physical activity has immediate health benefits by reducing anxiety and blood pressure and improving sleep quality and insulin sensitivity (which lowers the risk of pre-diabetes and type 2 diabetes).
Meeting the physical activity recommendations consistently over time can also lead to the following long-term health benefits:
- in youth, it can help improve cognition, bone health, fitness, and heart-health and reduce the risk of depression
- in adults, it helps prevent eight types of cancer (bladder, breast, colon, endometrium, esophagus, kidney, stomach, and lung); reduces the risk of dementia including Alzheimer’s disease; reduces the risk of heart disease, stroke, high blood pressure, type 2 diabetes, depression, and deaths from all causes; and improves bone health, physical function, and quality of life
- in older adults, it lowers the risk of falls and injuries from falls
- in all groups, it reduces the risk of excessive weight gain and helps people maintain a healthy weight.