10 indicators that you may need to take a rest day

If you don’t take time for proper recovery, your body won’t adapt to the stress of your training – you won’t get stronger or faster, explains Stacy Sims at the Stanford Prevention Research Centre, School of Medicine, US. Neglect recovery for too long, and you will start to lose strength and speed.

Your sleep patterns and energy levels will feel the effects first. Eventually, your immune system crashes and you lose your appetite. It’s like burning out your engine. And you don’t have to be logging 100 miles a week to suffer: recreational runners can overtrain, too. “With deadlines, chores, bills, kids and a lack of sleep, it’s more challenging to recover properly from your runs,” says Sims.

Pay attention to the following 10 markers. If three or more of these indicators raise a red flag, you should consider a few easy sessions or ‘off’ days so you can return to running strong. “Now I’m learning to love rest,” says Hall.


You've lost weight since yesterday.

A two per cent drop in weight from one day to the next indicates a body fluid fluctuation. It’s most likely that you didn’t hydrate enough during or after your last workout. Dehydration negatively impacts both physical and mental performance, and could compromise the quality of your next workout.


Your resting heart rate is elevated.

Take your pulse each morning before
you get out of bed to find what’s 
normal for you. An elevated resting 
heart rate is one sign of stress. It means your nervous system has prepared for fight or flight by releasing hormones that speed up your heart in order to move more oxygen to the muscles and brain. Your body won’t know the difference between physical and psychological stress. A hard run and a hard day at work both require extra recovery.


You didn’t sleep well – or get enough.

A pattern of consistently good sleep will give you a boost of growth hormones, which are great for rebuilding muscle fibres. Several nights of bad sleep in a row will decrease reaction time along with immune, motor and cognitive functions.


Your urine is dark yellow.

This can be an indicator of dehydration, barring the consumption of vitamins, supplements or certain foods the evening before. The darker the colour, the more you’re struggling to retain fluid because there’s not enough to go around.


You’re run down.

If your energy levels are low, there’s something amiss. The key is honesty. Athletes can block out signs of fatigue to push through it, thinking it will make them stronger. But it won’t always work that way.


You’re irritable

When your body is overwhelmed by training (or other stressors), it produces hormones such as cortisol that can cause irritability or anxiety. Stress also halts chemicals such as dopamine, a neurotransmitter in the brain that has a negative effect on mood when depleted. Crankiness probably means not enough recovery.


Your oxygen level has dipped.

The amount of oxygen in the haemoglobin of the red blood cells can be measured by placing your fingertip in a portable pulse oximeter, a gadget available online for about £20. The higher the percentage, the better: above 95 per cent is the norm at sea level or for an athlete who is fully acclimatised to a given altitude. This is a new area in recovery science, and it requires more research, but there may be a link between low oxygen saturation and the need for more recovery.


You're sore or nursing an injury.

Whether you’re aching from overworked muscles or you’re suffering an injury, your body needs more energy to put towards repair, lengthening total recovery time.


Your workout went poorly.

This is a subjective measure of workout quality, not quantity nor intensity. If you felt great on yesterday’s run, you’d evaluate that as good. If you felt sluggish on that same run, you’d count it as poor. Multiple ‘poor’s in a row is an easy way of identifying the need for more recovery.


You’re sick.

Any illness, or even a woman’s menstrual cycle, will increase your need for energy to refuel your immune system, which is having to work overtime. This means there are fewer resources available for recovering from training.