Have you been prescribed any medications because of your knee?

I also tore my ACL awhile back (and then re-tore after surgery, but that's a different story), and noticed the same thing. When you lift, the hormones that build muscle and promote recovery are elevated. Unfortunately, the same hormones also cause oily skin and hormonal acne.

No weight lifting = lower baseline hormonal levels = less oily skin = less acne

It blows, but we have to figure out what is most important; for some people (myself included) we simply can't look like a bodybuilder without some acne. It's in our genes.

I'm attempting to back off the lifting personally in an attempt to tone back my hormones a bit, and see if that does anything.

CBIOT13 hit the nail on the head. Exercise, especially weight lifting, stimulates the same DHT (dihydrotestosterone) activity that starts the acne inflammation chain.

When I still had acne, my skin was always better during lazy times (AS LONG AS my eating habits didn't change...if during vacation you eat a lot of carbs and junk, well, you're just upping your insulin and stimulating DHT anyway).

I have noticed the same thing. I have been very active the last 6 months. Lifting 3-4 times a week and I think my skin has worsen during that time. I think my skin is a lot better during lazy times as well! I guess we are unlucky BP seems to keep me 70-80 % clear though.

Another thing I have thought about is supplements to build muscle. Are you using any supplements like Whey Protein Powder? During my last 6 months I had like 2-3 shakes a day. The last 3 weeks I haven't had any shakes and my skin seems better.

I do regular cardio exercise, and I don't really breakout from it. I'm a runner-- so I run all the time. I have clear days and not-so-clear days.

But when I throw in my lifting routine, my face decides it hates me. It's definitely the hormone/DHT issue. Boo. I know it stinks. Especially for guys who (usually) want to lift a lot more often than girls. When you get better, try just doing cardio for a while and see if that doesn't exacerbate your acne.

Don't forget the most diet shakes (SlimFast) use whey protein or soy protein concentrate.

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Sweating during exercise could also be a factor. Also, were you taking any medication (e.g. anti-inflammatory) after your surgery? 'Cause that might be another reason that your skin changed.

I wonder if you are clearer now because your food intake has naturally dropped a bit? I am quite active, and I don't need to eat as much on my rest days. I am not saying that food breaks you out, though. What I have found to be my biggest triggers are stress, an unbalanced (promoting blood sugar spikes) diet, and hormonal stuff that is probably not a problem for you if you are a guy. I couldn't believe how much less inflamed my face became when I started eating more protein and less sugar. And it's been pretty good for a whole month! Hopefully that can continue. It makes me think that my inflamed acne was due to unstable blood sugar. Maybe the same could be true for you? And if you are eating less overall, maybe you are eating fewer foods that cause your blood sugar to spike? Just a thought; obviously I don't know what your diet is like. Something to consider though. Also, sorry to hear about your knee, but maybe this will help you identify what your skin triggers are. Silver lining.

Thanks for all the replies guys!

My diet typically consists of pretty high protein and some dairy. I have had to up my food intake while lifting, just because I get so hungry afterwards. A typical meal day is

6-7am 3 eggs scrambled, yogurt + blueberries

10am whole grain cereal, 1% milk

1pm turkey sandwhich, clif builders protein bar (chocolate +peanut butter)

5-6pm dinner, either pasta, fish, chicken with vegetables.

I don't typically eat a bunch of sugar, and I didn't really change anything during my sedentary period. Which makes me think it's just lifting activity .

I was on percocet for 3 days post surgery, but that kind of messed with my blood pressure so I got off of it and just took high dose Tylenol.

Before I did lifting I would do the Insanity program, and my acne was still pretty bad. But i'm somewhat convinced that was more of a sweating issue. I would try to get in the shower immediately after, but it didn't really seem to help much.

NEXT QUESTION: Should i go on Accutane? Will that help? Thanks!

Lifting heavy breaks me out and makes my skin very oily. I can do light exercise like pilates, though, and not have any issues. It sucks because I have the motivation to workout very hard, but my skin keeps me from doing that. At least pilates keeps me tone with little muscles, but I still wish they were bigger lol.

As for going on accutane, I think it will help to some extent, but you may still have the breakouts from heavy exercise after your course. I took accutane, and 3 years later I break out from heavy exercise still.

I'm in a similar situation. 26 years old and have had acne all of my life basically. I notice that lifting and exercising always makes it worse. I am finally giving in and going on Accutane in a few months. Life is too short to be worrying constantly about if the next workout or next thing you eat are going to break you out.