Dr Rebecca Lawson
Recovery Is Where the Progress Happens
It is easy to think of a rest day as a gap in your training — a pause in the good work. In reality, the opposite is true. The session itself is only the stimulus; the improvements in strength, stamina and body composition arrive afterwards, while you sleep, eat and take it easy. Skip that part and you are essentially making withdrawals without ever paying anything in.
When you train, you create tiny amounts of stress in muscle fibres, deplete glycogen stores and fatigue the nervous system. In the 24 to 48 hours that follow, your body repairs the tissue, refills those fuel stores and adapts to cope better next time. This is why two hard sessions back-to-back targeting the same muscles rarely deliver twice the benefit — but often deliver twice the fatigue.
What a Good Rest Day Actually Looks Like
Rest does not have to mean lying on the sofa, though occasionally that is exactly what your body needs. Think of rest as a dial rather than a switch.
- Full rest: a day off from structured exercise. Ideal after a long run, a heavy leg session or a demanding event.
- Active recovery: gentle movement that raises your heart rate only slightly — a 20 to 30 minute walk, an easy swim, a light cycle or a mobility session. You should be able to hold a conversation throughout.
- Deload weeks: every four to eight weeks, reduce your usual training volume by roughly 30 to 40 per cent while keeping the movements familiar.
Most people do well with one or two full rest days a week and active recovery on the days between hard sessions. A simple rule is never to place two demanding sessions for the same muscle group or the same energy system back-to-back.
Sleep: The Most Powerful Recovery Tool You Own
If you only change one thing, change this. Most adults need seven to nine hours, and consistent timing matters as much as total duration. Going to bed and waking at roughly the same time each day — weekends included — helps your body clock settle, which in turn improves sleep quality and daytime energy.
Practical steps that tend to make the biggest difference:
- Keep your bedroom cool, dark and quiet; a room around 16-18°C suits most people.
- Avoid caffeine after early afternoon. Its effects can linger for six hours or more.
- Be honest about alcohol. A drink may help you fall asleep, but it tends to fragment sleep in the second half of the night.
- Dim screens and bright lights in the hour before bed, and try to get daylight within an hour of waking.
- If you train in the evening, allow a proper wind-down so your heart rate and alertness can settle before lights out.
Eating and Drinking on Lighter Days
A common mistake is to treat a rest day as a day to slash calories. That can leave you under-fuelled for the next session and slow down repair. Keep protein consistent — around 1.4 to 2.0 grams per kilogram of body weight per day for most active adults — spread across three or four meals, and keep carbohydrate in the picture, particularly if you have been training hard.
Hydration matters too. Aim for pale straw-coloured urine across the day, and replace fluids after sweaty sessions rather than saving it all for training days.
Warning Signs That You Need More Rest
Fatigue is normal after hard training and should ease within a day or two. Persistent fatigue is different, and it is worth acting on. Look out for:
- A resting heart rate that stays five to ten beats above your usual baseline.
- Soreness that lingers beyond 72 hours, or niggles that keep returning to the same spot.
- Sleep that becomes broken or unrefreshing, even when you are tired.
- Performance that plateaus or slips despite consistent effort.
- Irritability, low mood, loss of motivation or a general sense of heaviness.
- Picking up colds or infections more often than usual.
If several of these apply, take two or three easier days and see how you feel. If fatigue persists for more than a couple of weeks, or you are also experiencing unexplained weight loss, changes to your menstrual cycle or low mood, speak to your GP. Persistent fatigue can have causes beyond training, including iron deficiency, thyroid problems and, in some cases, relative energy deficiency in sport.
Making Rest a Habit, Not an Afterthought
The most reliable way to protect recovery is to plan it. Put rest days in your diary with the same seriousness as your sessions, and treat them as non-negotiable appointments. Decide in advance what you will do — a walk, a stretch, an early night — so the day does not simply drift.
It also helps to reframe what you are measuring. Progress is not the number of sessions you complete; it is the adaptation you keep. A well-rested body trains harder, moves better and stays interested for longer. Rest days are not a reward you earn once you have done enough. They are part of the programme — and for most people, they are the part that makes everything else work.
