Specificity is crucial. Golfers should play golf to get ready for 18 holes. Football players should play football to get ready for all 4 quarters. Trapeze artists should practice the trapeze. Train specific to your sport, including the time component.
BUT When it comes to just being fit and healthy....
Intermittent exercise is just as good as continuous. For example, walking 10 minutes 3 times per day is just as good as walking 30 consecutive minutes.
Try developing small habits like walking around the mall twice, taking the stairs, walking around the block 3 times per day, riding your bike to work, or standing up at work.
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