Start tiny

Why start with a tiny habit?

Because small amounts of activity count, and a small action is easier to repeat. Current guidelines say some physical activity is better than none. Bouts of moderate-to-vigorous activity count towards goals whatever their length, which replaces the older 10-minute minimum [1]. The WHO 2020 guidelines give 150–300 minutes a week of moderate activity as a target to build towards, not a starting requirement [4]. US guidelines say health benefits can start with small amounts of activity, and soon after starting [2]. For older adults, many benefits occur at levels below those recommended in the US guidelines [5]. In observational studies of replacing sitting with activity, less active people tended to benefit the most [6].

Small actions also suit the way habits form. In one analysis, simple actions such as drinking water became automatic faster than elaborate routines such as doing 50 sit-ups [7]. In a 6-month trial of 339 adults with prediabetes (mean age 55), a programme built on small-step, individually tailored goals increased physical activity more than the control group (effect size 0.49). The authors link this partly to the confidence that comes from achieving goals [8].

Expect a habit to take a while. In a meta-analysis, the median time to form a health habit was 59–66 days, but individual times ranged from 4 to 335 days. Most of the studies were at high risk of bias, so no single number is reliable [3]. Missing one day is not a setback: in a 12-week study of 96 volunteers, missing one opportunity did not materially affect habit formation [9].

You can also build movement into daily tasks. In a systematic review of older adults, fitting balance and strength exercises into everyday tasks improved balance, strength and function in people living in the community [10].

What is habit stacking?

Habit stacking means attaching a new tiny action to something you already do, so the existing routine becomes your reminder. The research behind it calls these 'if–then plans' and does not use the term habit stacking. An if–then plan links a specific situation to a specific response: 'Whenever situation x arises, I will do y' [11].

In a meta-analysis of 94 independent tests, if–then plans had a medium-to-large positive effect on goal attainment (d = .65). The tests covered many behaviours, not only physical activity [12]. For exercise, a systematic review of 24 studies found that earlier results were mixed. The plans worked best for people who already intended to be active and felt confident they could be [13]. If the plan feels hard to keep, that does not mean you have failed. It may simply need changing.

Here is how to write one: 'After I [existing routine], I will [tiny activity].' For example, 'After I make my morning coffee, I will walk around the block' or 'After I brush my teeth, I will do 10 calf raises.'

• Choose a routine you do every day, and keep the new action very small.
• Use the same place and situation each time. In the 12-week study, volunteers repeated a daily behaviour in the same context, such as 'after breakfast', and it became more automatic with repetition [9].
• Review the plan if it stops working. In a large UK trial (7,835 people), a single planning exercise did not prevent face-covering use from declining over 6 months. That is not a physical activity outcome, but it suggests one plan made once may not be enough [14].

Some small studies suggest it may help to place a new action after an established routine rather than before it. In a study of dental flossing (50 people), those who flossed after brushing tended to form stronger habits. This is not physical activity evidence, so treat it as a hint only [15].

When should you check with a health professional first?

Walking and other light-to-moderate activity are a safe starting point for most people. Check with a health professional first if you have a heart or lung condition or diabetes, are pregnant, are recovering from surgery or injury, or are frail. Keep your tiny action light, and build up gradually.

Stop and seek medical advice if you notice chest pain or pressure, unusual breathlessness, dizziness or fainting, or pain that is sharp or getting worse.