text: Too Tired to Train Today?. One simple test to find out if you're… | by Jamie D Stacey | In Fitness And In Health | Medium
  One simple test to find out if you're overtraining — and to prevent a wasted workout
  Some days I'm Hercules, or Dwayne Johnson, just tapping into an infinite well of energy, motivation, a "I can do this" attitude. Other days I'm a sloth, or a Snorlax, just sinking back under the quilts, duvets, and the only weights I feel like lifting are some extra pillows.
  I'm tired. You know? And yet I still want to train. Or at least I tell myself I should be training. You sympathise?
  The question here is: when are we too tired to really train?
  In part, it depends on your goals. If you're looking to build a Spartan resilience or pass a Navy Seal test, fighting fatigue can toughen your mind and push you to new limits of possibility. This is something I've tapped into on a few occasions. It's a different breed of training, it's a soldier's mentality.
  But this can also be damaging, especially in the long-term (even soldiers need rest). Moreover, if your goal is more about athletics, hypertrophy, or weight loss, then maintaining 100% form and a solid recovery are important. "Overtraining", that is, not recovering enough, can greatly affect your goals as well as increase the risk of injury.
  But I get it, you feel that you should be training.
  So, how do you know if you're too tired? How do you know you're not going waste your workout?
  Let's train (or not).
  If you're regularly clocking in under 7–8 hours of sleep, or you're not eating normally, or you're feeling less Dwayne Johnson and more Mr Grumpy, then you may well be chronically fatigued and that's the first thing to tackle. Take a few days, or even a week off. Recover, reassess, rest.
  Drinking enough water is also important. A loss of sweat equal to just 2% of body weight can notably reduce performance, whilst a loss of 5% or more during physical activities may decrease the capacity for work by roughly 30%. Many adults don't consume enough water, and this is especially important for exercise and also when considering environmental conditions, such as high heat.
  Beyond this, look out for an abnormal resting heart rate, or excessive heart rate variability. Both may indicate fatigue that merits attention.
  Finally, keeping a record of your performance allows you to check fatigue levels across days and weeks. "Overtraining" will not only show up as a plateauing in your weekly results, but may even show a progressive dip. It's also useful to look for how many consecutive weeks you've been following a program. We all benefit from a rest or "easy" week, usually every 4–6 weeks. You'll be back fresher and readier than ever.
  In essence: look for these warning signs, and make time for proper recovery.
  And what about that murky grey area — you're tired, but maybe not that tired? What is too tired to train without wasting your workout?
  One useful indicator is to test your grip strength. Why? Because your baseline grip strength is the great hidden storyteller of your overall strength and state of recovery.
  "We know that there's a high correlation between your central nervous system (CNS) and the output in grip strength to test how well a player is recovering" — Jeff Cavaliere.
  So, how to use grip strength as a measurement to gauge overtraining and recovery?
  1/ Test your baseline grip strength every day to keep a record for comparison. You can use a hand grip dynamometer or, for a slightly less accurate but more readily accessible way, a bathroom scale.
  2/ Be consistent. If you test your grip strength first thing, then test it every day. Learn what your average is, get a sense of how this feels.
  3/ Apply the method regularly to know if you're overtraining or too tired on a given day. If you're falling below your average recordings, that's a clear sign that you haven't recovered from the previous session(s). Take a break. Your body will thank you later.
  Overtraining, Recovery, and Grip Strength
  Part of the beauty of fitness is learning about our bodies, their potential and also, alas, their limits.
  Learning to 'read' our bodies — the signs it gives us when we're fatigued or tired—is important. That's not to say that we shouldn't push ourselves occasionally.
  When I tested for my brown belt in Kyokushin Karate, I had to train 24 hours in a 48-hour period at a 'bootcamp', ending with "surviving" a 10-round bout with 10 different fighters. It wasn't a fight; it was a beating. I returned home exhausted and depleted. But then I rested and recovered. And I learnt how much I can really be pushed and, ultimately, I discovered new limits.
  But these are exceptional. Generally speaking, we want to be mindful of recovery and our state of readiness. Besides the usual telling signs, testing our grip strength regularly is a great indication of whether we're too tired to train. I've even learned to get a "feel" for when my grip is weak simply by picking up the shopping bag or my toddler. When I'm really tired, I know not to fight it.