T Nation

How Does TRT Affect Cardio?

I’ve been on TRT for about 2 months now 200mg a week I’ve noticed positive body recomp in my traps and shoulders weight has gone from like 224-229 while my belt size is actually getting looser. Gym lifts are going up and everything is getting easier but I am also a runner and I have noticed my runs are actually getting worse. I am feeling more fatigued and my times are getting worse. Just wondering if this is related to the test at all.

What do you guys think, do we have any runners in here that are on test or trt? How has it affected you?

I am not on any AI or anything ele.

We need labs to be able to assist you, if you are on the wrong protocol given your SHBG, I would expect poor results. There are some men who don’t do well on once weekly dosing as levels are declining quickly and levels are lower at trough, these swings in levels can make TRT less effective.

If SHBG is on the lower end, this would explain your results. Your comment about things getting worse over time suggest you are not on an optimal injection frequency.

Thyroid is also responsible for energy, thyroid hormone fuel every organ and cell in your body.


My cardio has done nothing but get better while on trt. More RBC means better cardio. But it takes longer than two months to really be noticeable. For you it could simply be that you’re growing muscle—which is taxing on a cellular level, remember—and you’re adding some weight to your frame. Cardio for you may improve over time but lag at the beginning. Everyone reacts a little differently to trt.


I noticed increased endurance, but for me high reps is five. Testosterone increases erythropoietin which increases red blood cells and therefore oxygen carrying capacity of the blood. This is why endurance athletes use test and anabolic steroids. Think Tour de France.

My initial guess would be fluid retention but it doe not sound as though that is the case for you. Could be as simple as a little weight gain.


When I first started my TRT protocol I noticed increased fatigue, heavier legs, and more lethargic runs at first. After about 2-3 months this leveled out and got better, and now about 8 months in to TRT my running speed and endurance is better than it’s been in years. So give your body time to adjust, keep up the running and wait for things to improve.


I noticed the same thing. I started about 2 months ago on Cypionate 200. I do .5 mL twice a week and about 3-4 weeks in I went from being able to make it 3 miles at about a 10 min/mi pace to being able to only run a mile to 1.4 miles before having to walk due to my calves and thighs feeling so swollen that I couldn’t go anymore. My anterior tibialis got so swollen at times that I started to get drop foot while running.
I am 6’3” tall and went from 258 lbs to 272 lbs in the last 2 months. So some of the difficulty I attribute to the weight gain but the swelling and tightness in my legs is making it so I can’t run. I have been running for 6 years prior to starting TRT.

Temporarily switch to riding a bike.

Thank you. Yeah I did some more research and I’m going to do some HIIT with running and biking for a while until this passes.

If you are low SHBG you may have issues with injections frequency

It is logical to have increased cardio performance. Since I started TRT Ive gained 10kg(Im a pig and starting diet now) but my cardio has improved significantly.

Also when I was riding snowboard in the winter I noticed increased endurance, even when I had to get out of the deep snow by feet in the off piste riding

I do crossfit and I’ve only noticed an increase in endurance (and recovery) on TRT over the past 5 years. I think it’s the increased red blood cells that make me able to work out longer and harder during a workout. I used to get winded quicker and not be able to finish some workouts pre-TRT.

Thank you for the reply. I have to clarify that I do see an increase in endurance. My problem is that wile running my calves and thighs get so tight and fatigued that it makes it impossible to run longer than 1-1.5 miles before having to walk where I was able to run 3 mile before without stopping. It’s not due to my cardio but my calves get so swollen while running that I start to get drop foot temporarily due to compression on the deep peroneal nerve. Hopefully that helps clarify my question sorry for the confusion.