Why Your Blood Test Might Look “Off” After a Tough Workout

July 26, 2025•3 min read

At Empower, our members who take their health seriously. That means they’re not just putting in the work at the gym — they’re also getting regular check-ups and blood work to track things like inflammation, hormone levels, liver and kidney function, and overall wellness.

But here’s something I didn’t realize until recently:

Intense exercise — especially heavy lifting or high-volume conditioning — can actually skew your blood test results.

Wait, What?

I had some routine blood work done recently. A few markers came back outside the “normal” range. I felt a little perplexed. But then I started wondering… could the workouts I’d done that week have had something to do with it?

I've been training hard — in the gym four to five times a week. I did mention that to my doctor, but I don’t think I emphasized the intensity or the type of training enough. And maybe that mattered more than I realized.

So I started digging. (Let’s be clear: I’m not a doctor, and this is not medical advice. This is just what I found through my own research and experience. If something on your blood test looks off, please don’t ignore it — talk to your healthcare provider.)

That said, I thought others might find this helpful too — especially if you’re someone who lifts regularly or trains hard at Empower.

How Exercise Can Skew Blood Work

Exercise is stress. Good stress — but still stress. When you lift heavy or push hard, your body responds by breaking down muscle, triggering inflammation, and releasing various enzymes and hormones to recover and rebuild.

This can cause short-term changes in your blood — changes that might show up on a lab report and raise a few eyebrows.

Markers That Might Look Elevated

According to Google, here are a few common ones that can be affected by training:

Creatine Kinase (CK)

CK goes up when your muscles are repairing from damage — which is exactly what happens after lifting weights. High CK levels are normal for athletes, but without context, they can be mistaken for something more serious (like rhabdomyolysis).

Liver Enzymes (AST and ALT)

These markers aren’t just in your liver — they’re also in muscle tissue. After a tough workout, especially one involving heavy lifting or eccentric movements, these levels can rise. That doesn’t necessarily mean there’s anything wrong with your liver — but it can look that way on paper.

C-Reactive Protein (CRP)

CRP measures inflammation in the body. After a high-intensity or especially novel workout, CRP can spike temporarily. Again, not always a sign of illness — sometimes it’s just your body doing its thing.

White Blood Cell Count (WBC)

Exercise causes a stress response in your body, and part of that response is a rise in WBCs. If you test right after a workout or during a recovery period, you might see higher-than-usual levels.

How to Get More Accurate Results

If you’ve got blood work coming up and want the clearest picture of your health, the general recommendation seems to be:

Take at least 48 hours off intense training beforehand
Ensure you're hydrated
Let your doctor know how often and how hard you train

Some sources even recommend a full week off before testing — especially if you're doing a lot of volume or intensity. When I go for my follow-up tests, I’m definitely going to take it easy the week before. No hero WODs for me (oh dang!).

But again: if something looks off, don’t ignore it. Always talk to your healthcare provider. The goal isn’t to dismiss the numbers — it’s to understand them in context.

And if any of our members have expertise in this area, I'd love to get your take!

Here’s an interesting case study on exercise and liver function tests.