Making the appropriate rest periods an integral part of your training is non-negotiable. We check in with the experts – and the science
WORDS David Leck
When rest periods between sets are too short you risk fatigue, injury and unwittingly shifting the emphasis away from those hard-earned goals.
Too long a pause and cooled muscles may be under strain, leading to tendon stiffness and even a reduction in the essential components that control movement and muscle contraction and that, crucially, drive the chemical messengers the brain releases during and after exercise.
All of this, of course, depends on the type of training but it’s a reminder our bodies are complex and, like it or not, you can’t out-train science.
“Physiologically speaking, skipping rest between sets can reduce performance, affect your results and increase fatigue,” says Louise Wright, who is the physiology national lead at Nuffield Health and holds a BSc in exercise and sport science from the University of Exeter.
“Exercise, rest, and recovery should be seen as a cycle rather than separate entities. Training challenges the body, rest allows for priming in the short-term and repair in the long-term, and recovery facilitates adaptation. Neglecting any part of this can lead to burnout, injury or stagnation.”
Wright cautions your meticulously planned training regime and hours spent on the squat rack could be, if not squandered, then vastly reduced without paying attention to rest.
“Too few rest periods can lead to fatigue which may not only reduce performance but shift the training effect toward metabolic stress [impacting the processes that convert food into energy and the materials our bodies need] rather than strength or power. Too much rest can reduce the training stimulus. If prolonged, there is a risk of loss in training-induced adaptations [“gains”, to you and me].”
Wright believes a little understanding of the science is an easy fix on route to ensuring smatter training.
‘In terms of fatigue – and without rest – there is an impact on the motor unit recruitment in the muscles,” she says. “High threshold motor units ([such as your type II fibres – those fast-twitch little guys] fatigue quickly and need time to recover. Prolonged effort also reduces cortical drive and neurotransmitter availability [such as dopamine – our mood and reward hormone].
“And if we’re looking for longevity in training, something people don’t always consider is the impact inadequate rest has on proprioception and joint stability. In addition, fatigue impairs movement precision and – if training complex lifts or movements where things like alignment and timing are vital – the risk of injury increases.
“It’s also important to note muscle temperature can drop with inactivity in as little as three to five minutes, reducing contraction efficiency. This is especially important if training in cooler environments as performance may be compromised.
“Cooler muscles are less ‘pliable’ and can be subject to strain, leading to things such as increased tendon stiffness. Your central nervous system arousal may also decline, especially in explosive or compound lifts.”
Optimise recovery
Alex Crockford is founder of a self-titled app boasting thousand of subscribers as well as having some 400,000 Instagram followers.
“It’s one thing doing workouts; it’s another optimising your recovery. When you recover better, you’re able to workout again sooner and harder, leading to quicker and better results,” he says.
“The whole topic of rest periods can be confusing and it’s up to a good trainer to educate a client. Rest periods are integral to the design of every element of my app and the programmes I offer clients across training cycles and methods.
“This always comes back to your goals, whether that’s getting strong, building cardiovascular fitness, or increasing size and muscle mass.”
Crockford argues much of this is made unnecessarily complex but, in the end, it’s back to some fundamentals: understanding the importance of rest, those all-important goals, finding your training ‘sweet spot’, and listening to your body.
“Put simply, getting the most out of every rep requires your energy systems to recovery before moving onto that next set.
“With hypertrophy [size], you’re looking for muscle fatigue – that burn and lactic acid build-up. You’re stressing as many of the muscle fibres as you can because, as we know, stress equals change and change equals growth. But you don’t want to rest too long as muscles will go cold.
“I typically suggests 60 to 90 seconds. Any longer and you’re starting to recover too much. If, though, you’re doing a giant superset you may be able to increase that to two to three minutes. With isolation exercises and smaller muscles, you’d reduce rest to maybe 45 seconds.”
Kim Bergman is a former gymnast who represented his homeland of Sweden before turning to coaching. For the past decade he’s owned and run the Against the Fire CrossFit gym in south London.
“You can’t treat every session the same. Two people might do the same movement but need totally different rest times based on goal and conditioning.
“When I design programmes, I build rest into the workout. It’s not a suggestion; it’s part of the training. It’s also needed to ensure an efficient use of time. As an example, if you’re doing five sets of five heavy squats, those two or three minutes of rest each time can eat into your workout window. That’s where accessory moves [lunges, for example] come in to target glutes and hamstrings without overrunning the session.”
Each to their own
Bergman adds rest is personal but it’s not optional. He says, for someone new to the gym or less fit, even three minutes might not feel long enough while – for an experienced athlete – it could be plenty.
And then there’s the avalanche of information, tips and ‘golden bullets’ from the army of online ‘experts’.
“There is often way too much talk about the ‘perfect’ way to train but really there’s no such thing. The only constants are that you need to listen to your body, train smart, and respect the rest as much as the hard work,” says Bergman.
It’s a mantra that chimes with Alex Crockford.
“When you first start training – or even if you’re seasoned in the gym – you can think you’ve hit your limit. But your body and mind adapt. A month later, you’ll do the same set – maybe heavier – and it’ll feel easier. That’s progress but progress demands rest and recovery.”
We asked Louise Wright to delve deeper into the vital role this plays in effective training.
“Recovery encompasses both passive and active strategies helping the body return to a state of balance. Passive recovery includes sleep, hydration and nutrition, while active recovery might involve light movement, stretching, massage or mindfulness practices.
“Effective recovery enhances circulation, reduces muscle soreness and restores energy. It also supports mental clarity and emotional wellbeing – key factors in maintaining motivation and consistency. Recovery is not just about physical repair; it’s about creating the conditions for sustainable progress.”
In addition, modern lifestyles, diet and stress have rendered – at least in part – any correlation between age and fitness performance redundant.
Wright says that, with ageing, there are biological changes such as a decline in both mitochondrial efficiency [the generation of the chemical energy needed to power the cell’s biochemical reactions] and anabolic resistance [a reduced ability for muscles to respond to stimuli that typically promote muscle growth] as well as the more obvious factor the time required to restore the body’s central nervous system increases.
“We need to consider experience levels and lifestyle can have a positive impact and can offset chronological ageing impacts – a fit and regularly training 50-year-old is likely to outperform a sedentary 20-year-old. However, at a base level, it may be older people could benefit from more structured rest strategies to optimise performance and reduce injury.”
Age is a factor
Even considering age isn’t necessarily an accurate measure of an individual’s fitness, there are clearly considerations as we clock up those years in the gym or on the sports field.
“It’s about how you live – how you eat, sleep, train and look after yourself. Age isn’t the barrier people think. And I know I’m forever saying this to clients but don’t compare yourself. Be inspired by those around you in the gym – that’s good and you can certainly learn from others – but this is about you and your body,” says Crockford.
“As we get older, most people need more rest periods between sets and sessions as recovery just takes longer,” adds Bergman. “That said, I’ve got people in this gym in their 50s and 60s way fitter than many 25-year-olds.
“Everything in training is nuanced. You can ask 10 coaches the same question and get 11 opinions. What matters is how you train, what you know, and how you apply that knowledge.”
Louise Wright highlights the dangers of stagnation and failing to progress as real but says they’re easily rectified.
“There is nothing more demotivating for someone working hard in the gym [and I do mean working hard] than not seeing results equal to their effort. Even worse, we know demotivation can lead people to simply throw in the towel.
“This can be avoided by acquiring a little knowledge around the science of how you train and understanding things like the role of rest and recovery. You’re doing the work so why wouldn’t you want to give yourself the best chance of maximising results, staying on-track with your goals and – yes – enjoying your training?”
