Do meditation and breathing exercises help you recover?

Short answer

No. Slow breathing did not raise strength on the next set or fitness gains after 4 weeks. It did lower stress a little, and meditation improved sleep quality a little.

Do meditation and breathing exercises help you recover?
'Slow breathing → body switches to rest mode → faster recovery' — does this formula hold?
A popular idea is that slow breathing or meditation relaxes your body, flips it into rest mode, and speeds up recovery from training. Lots of athletes do it. We checked whether this formula actually leads to better recovery of performance.
What about slow breathing between sets?
Heart rate dropped faster, but strength was the same
18 people did 5 sets of 3 squats, breathing in for 4 seconds, holding for 7 and breathing out for 8 during the 3-minute rest between sets. During the 3-minute rest after set 2, heart rate fell by 51 beats per minute, more than with normal breathing (44.5). But strength and bar speed did not differ.
Does doing it daily for 4 weeks change things?
Fitness gains were the same, and night heart rate actually rose
34 people did sprint interval training for 4 weeks, and half added 10 minutes of slow breathing after training and before bed every day. Both groups improved by the same amount. The breathing group's heart rate during sleep rose by 3.1 beats per minute more.
What changed was the feeling, not the body
People felt more recovered, but heart measures were the same
13 people practiced breathing 6 times a minute for 7 weeks. Those who practiced scored better on feeling recovered and on feeling that training was going well. But body measures like heart rate and heart rate variability, and stress scores, did not differ.
So does it lower stress?
Yes, both breathing and meditation lowered it a little
An analysis that pooled 12 trials with 785 people found breathing practice lowered how stressed people felt. An analysis of 47 trials with 3,515 people found meditation eased anxiety and depression a little. An analysis of 58 studies with 3,508 people found meditation and mindfulness lowered the stress hormone cortisol.
Does sleep get better?
A little, but it did not replace sleep treatment
An analysis that pooled 18 trials with 1,654 people found meditation improved sleep quality a little compared with spending the same time on another activity. But compared with proven insomnia treatments, there was no difference. Think of it as a helper for nights you can't fall asleep.
Bottom line: it's a tool for the mind, not for muscle recovery
The formula breaks at the 'faster recovery' link
Slow breathing brought heart rate down faster for a moment, but it did not raise strength on the next set or fitness after 4 weeks. What it did do was lower stress and improve sleep quality a little. Leave body recovery to sleep, food and rest days, and you can use meditation and breathing when you want to unwind.