Muscles don't grow while you're training. They grow while you recover from it. Rest isn't skipping. It's half the job.
The lie
"It's a rest day."
The short version
- Give each set of muscles about 48 hours before working them hard again.
- Do a little more over time. That's called progressive overload.
- Aim for 7 to 9 hours' sleep. It's the best recovery tool there is, and it's free.
Today's rep: Check your week: no two strength sessions on back-to-back days, and no rest days that aren't resting from anything. Jump to it
The seventh rest day in a row
A rest day comes after something. Otherwise it's a day with a sofa in it.
"It's a rest day" is a perfectly good sentence. On Wednesday, after Monday's session, it's true. On the following Tuesday, after six more of them, it's a lie wearing a dressing gown. A rest day comes after something. If nothing happened, it isn't rest. It's just a day, with a sofa in it.
The opposite lie is just as daft: training every single day because rest feels lazy, until something gives. Both are ways of not listening to your body. One just has better trainers.
Training asks. Rest answers.
Give the same muscles about 48 hours before working them hard again.
Training puts your body under a bit of stress. Recovery is when it adapts and comes back a little stronger. Skip recovery and you're just asking the same question louder. For beginners training the whole body, the American College of Sports Medicine suggests leaving around 48 hours between hard sessions for the same muscles.1 Monday, Wednesday and Friday works. Monday, Tuesday and Wednesday doesn't. Monday, and then nothing until the following March, also doesn't.
Progressive overload, in English
Do a little more over time. One rep, one step, five seconds.
It means doing a little more over time, so your body keeps having a reason to change.1 One more rep. The next rung on the press-up ladder. Five more seconds on the wall sit. A slightly heavier bag of shopping, carried slightly further, with slightly less swearing. Not all at once, and not every session.
Sleep
Adults need 7 to 9 hours.2 If you're getting five, no supplement on earth makes up for it, and the ones that claim to are lying to you in a nicer font. Same bedtime most nights, a dark room, phone out of reach, caffeine in the morning and early afternoon only (chapter 16), and go easy on the late pints (chapter 15).
Mostly for women
Men, this is about periods, the menopause and sleep. You can skip ahead. Or stay, and finally understand why the fan is on in November.
Sleep, your cycle and the menopause
In the days before a period, PMS can bring tiredness and trouble sleeping. The NHS lists regular exercise among the things that help.3 Around the menopause, night sweats and difficulty getting to sleep or staying asleep are common.4
On weeks like that, sleep is part of the session. Keep the training gentle, keep it going, and don't count a slower week as failing. It's recovery doing its job, on a harder shift.
Next: Mike Mentzer: right about some thingsBack to the contents
Mike Mentzer: right about some things
His principles hold up better than his rules. A fair verdict on Heavy Duty.
Mike Mentzer was a top American bodybuilder in the 1970s with a big idea he called Heavy Duty. His argument was that most people train far too much. Do very few sets, push every one as hard as is humanly possible, then rest for days.5 He was clever, persuasive, and quite cross about it, in the way only a man with a magnificent moustache and that many opinions can be.
So was he right? Partly. Here's a fair verdict.
Where he was right
- Effort matters. You have to work hard enough to give your body a reason to change.
- Doing more over time matters.
- Rest matters more than most people think.
- Low volume works, especially for beginners. A set or two per exercise builds strength when you're new.1
Where his rules go too far
- Every set to total failure, where you can't do one more rep. It isn't needed. Stopping a rep or two short works about as well for most people,6 and for beginners it keeps your form tidy.
- Very long gaps between sessions leave progress on the table.
- More weekly work generally builds more muscle, up to a point.7
The verdict: his principles hold up better than his rules. Train hard, rest properly, keep adding a little. Just don't treat every set like a duel at dawn with a man who insulted your family.
Your rep for this chapter
Check your week: no two strength sessions on back-to-back days, and no rest days that aren't resting from anything. Then set a bedtime alarm, not just a wake-up one.
The lie: "It's a rest day."
The short version
- Give each set of muscles about 48 hours before working them hard again.
- Do a little more over time. That's called progressive overload.
- Aim for 7 to 9 hours' sleep. It's the best recovery tool there is, and it's free.
Your rep
Check your week: no two strength sessions on back-to-back days, and no rest days that aren't resting from anything. Then set a bedtime alarm, not just a wake-up one.
Your browser forgets. Your photos don't. Save it, and the rep turns up in your camera roll at 7am when you're looking for something else.
Sources
1. Ratamess NA et al. Progression models in resistance training for healthy adults. American College of Sports Medicine position stand. Medicine and Science in Sports and Exercise. 2009;41(3):687-708.
2. NHS. Insomnia ("adults need 7 to 9 hours").
3. NHS. PMS (premenstrual syndrome).
4. NHS. Menopause and perimenopause, including the symptoms and things you can do pages.
5. Mentzer M, Little J. High-Intensity Training the Mike Mentzer Way. McGraw-Hill; 2003.
6. Grgic J, Schoenfeld BJ, Orazem J, Sabol F. Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: a systematic review and meta-analysis. Journal of Sport and Health Science. 2022;11(2):202-211.
7. Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis. Journal of Sports Sciences. 2017;35(11):1073-1082.