Does heavy lifting make you tired?

[Avocadocat]

I started strength training about a year ago, but only more basic machine stuff in the gym. I would call it strength training rather than weight lifting but have consistently trained 2 - 3 times a week for the past year.

I've run regularly for years and was running around 40 - 50 miles a week as standard, increasing before events. When I started strength training I dropped this to more like 40 miles a week. This was all fine - it was mainly gentle runs, trail running so lots of walking up hills etc.

Six weeks ago I started with a PT with the aim of lifting heavier weights, moving more towards squats and deadlifts. I've absolutely loved it and made real progress in those six weeks, pretty much doubling what I can lift in that time (I started, sensibly, fairly light). I train 2 - 3 times a week including these.

I've found I've had to drop the running to incorporate this and am now doing around 25 - 30 miles a week but I'm still absolutely exhausted. I know watches aren't that accurate especially for weight lifting but my Garmin says I bun far fewer calories in an hour of weights than I do running, and my exercise load is way down. The weight sessions don't feel as tiring as a run during them so I'm a bit confused.

It sounds almost a stupid question, but is lifting heavy weights, especially at the start tiring? I absolutely love it though 😃

Building muscle is tiring because it happens while you sleep - the reason children need more sleep despite having more energy than adults is because their bodies are growing (and they are doing more learning, which is building connections in the brain). You have presumably already developed the main muscles that you use to hike.

This would make a lot of sense thank you. It feels that perhaps a lot of the progress with weights happens outside the gym whereas the effort with my running seems to happen during it.

Heavy lifting (and I mean heavy compound lifts) can fry your central nervous system which can make you feel exhausted. Its not about the calorie burn necessarily.

Alternatively you might need to look at your pre and post workout nutrition. Are you eating enough?

Yes it can be tiring. The amount of calories you burn, even if that were accurate, is no indication of how tired you’d be. I compete in powerlifting and the run up to comp we are knackered as as the PP says it has a big impact on the central nervous system. We don’t sustain that all year round though. If you’re working with a PT mention it to them so they can help manage it. Plenty of food and sleep will also help.

I'm not sure on the eating enough. I find it difficult to work out compared to running. My watch tells me I only burn about 250 - 300 active calories in an hour of lifting compared to more like 800 when running so I haven't been eating so much. I wonder though whether weight training continues to burn more calories after I press stop.

Thank you - I'm going to look up more about the central nervous system.

You get strong during recovery, not the session itself.

It's a combination of muscles getting stronger and the brain organising the neural pathways that are needed for technical lifting.

Don't be watching your calories too much, it's not a straight in/out equation.

Yes you continue to burn calories after you stop the session. I’d ignore your watch. Listen to your body then adjust if it’s causing issues. When I first started lifting I had to eat in the night sometimes I was so hungry. I weigh less and have a shit tonne more muscle. And I have to make sure I eat enough all the time. And sleep.

This might also explain the waking up at 3 am hungry 😁🥴

The fatigue can hit you almost immediately. I'm back in my game of deadlifting and did 4 reps for 100 yesterday (non-stop - "touch & go" style) I then had a set of 5 for 85kg (after 2 mins rest), and it was harder than the 100s! You can really feel what heavy weights do.

I'm still tired 24 hours later, but I have done an hour of metcon this morning ...

When I tried to incorporate compound lifting three times a week into my running training (similar distance a week to you) I found it incredibly difficult to have any energy for running. I slept like a log every night and my running performance dropped right off. I struggled to put weight on, despite eating what felt like millions of tonnes of all the food. Then got too close to a big race so sacked the lifting off and running performance came back. I wish I could balance them well, just find it difficult to juggle everything I want to do and everything I have got to do!