Great Bodies, No Sex: Chronic Exercise vs. Libido

The Truth About Sex Drive and Overtraining

Can chronic overtraining kill the libido and sexual function of men and women? It appears so. Here’s what you need to know.

A few years ago, scientists examined the role of endurance exercise and sexual libido in healthy young men. Their study involved over 1000 men between the ages of 18 and 60. It was based on questionnaires – often prone to several problems – but the researchers went to great lengths to ensure the integrity of the answers.

The questions they compiled were culled from a variety of sources, all of which are commonly used in research/clinical settings. The intent was to find correlations between exercise duration, intensity of the workouts, age, and total libido score.

The survey was repeated every four months over a year and targeted men involved in various sporting activities (running, bicycling, swimming, lifting, etc.), many of whom were associated with organizations associated with endurance-training activities.

There were a whole lot of statistics to correlate and interpret, but the main points were as follows:

Training intensity and duration of training were most significantly associated with libido. Participants with the lowest and mid-range intensities had greater odds of high/normal libido state than those with the highest training intensity.

Participants with the shorter and mid-range training durations as their current intensity also had greater odds of high/normal libido scores than those with the greatest duration.

Loosely interpreted, training 1 to 16 hours a week (low “chronic duration”) makes you four times more likely to be in the normal or high libido range than those who train over 20 to even 40 hours a week (like some marathoners).

Of course, if you throw intensity in the mix, the results get murkier. If your intensity is high, the lower your training frequency and duration should be, at least in the long run. Your libido can handle short periods of balls-out training, but if it persists for weeks or months, say goodbye to libido.

The underlying message, as stated by lead researcher Anthony Hackney, is this: If you’re male and train for a large number of hours or it’s at a high intensity, your libido will decrease.

In practical terms, this means that training for marathons (races), training CrossFit style for months or years, or even five days a week of your classic cardio sessions, is going to wipe out your libido.

The Testosterone Factor

The Hackney study didn’t pay much attention to the effects of training or overtraining on testosterone. Still, researchers have long reported an association between overtraining and low resting hormone levels (and thus a low libido).

Even though the phenomenon has long been reported, organizations like the IOC have renewed interest in it, even coming up with a new term to describe it: Relative Energy Deficiency in Sports.

It’s a benign way of saying that exercise has mucked up the reproductive health of men and women who overtrain. It’s most often an acute syndrome, but there are those for whom it becomes a long, hard, persistent hormonal slog. Males who fall into this category are now said to suffer from “Exercise Hypogonadal Male Condition.”

The phenomenon also occurs in women who overtrain, but their pathology, as I’ll lay out below, is a little more complex.

But Wait, Other Studies Say the Opposite…

“Yeah, but other studies say that working out increases testosterone levels!”

That’s true. Working out generally increases testosterone levels. It also elevates sexual responsiveness in men and women. The magnitude of these increases in testosterone depends heavily on number of sets, number of reps, the order of exercise, and perhaps most importantly, choice of exercises.

For instance, a set of jump squats will increase testosterone levels more than a set of bench press (15% increase compared to a 7% increase). Generally, working bigger muscle groups elicits a greater increase.

The trouble is, this elevation of testosterone is often woefully short, especially in men who lift heavy. Then, to make matters even more puzzling, post-testosterone levels often dip below baseline, sometimes for days.

It could be because of cortisol’s antagonistic relationship with testosterone: Rising levels of cortisol induced by a tough workout bring testosterone levels down. That might well explain the chronic low libido seen throughout Hackney’s study.

However, there are a couple of other theories that might explain acute (but not chronic) post-workout dips in testosterone. After a hard workout, several things happen.

For one, testosterone converts to its metabolite, DHT, at a much faster rate, which would affect the total testosterone seen in a blood test. Not to worry, though, DHT is more anabolic than testosterone, so no harm, no foul in that regard.

Secondly, increases in testosterone increase the receptivity and responsiveness of androgen receptors (it’s this “androgen complex” that initiates muscle protein synthesis). That means that more testosterone would park its butt into the welcoming laps of androgen receptors, which would also show up as reduced testosterone levels in any blood test.

So that might explain the transient dips in testosterone often seen in strength athletes. However, it’s not the same thing that happens in chronically overtrained athletes, the type Hackney evaluated in his study.

What About Women?

Hackney’s study involved the effect of overtraining on the libidos of men, but there’s no reason to think the results don’t apply to women too.

However, most studies on female libido and arousal focus on the effects of a single exercise session. Their goal is usually to determine how female genitals respond to a workout, and, generally speaking, anything that increases blood flow to the area increases sexual responsiveness.

Likewise, short bouts of exercise trigger a female’s sympathetic nervous system (SNS), resulting in increased “vaginal pulse amplitude,” which is a polite way of saying that exercise makes women more likely to grow a female boner (an increase in vaginal engorgement).

But all of that pertains to short periods of exercise (usually less than 45 minutes) and not the hours-long, 5 to 7 days a week training sessions often associated with CrossFitters, marathoners, or the exercise addicted in general.

When females chronically overtrain, the most commonly seen problem is a disruption of the normal function of the pituitary/hypothalamic axis (just like in men) that manifests itself through lower levels of testosterone and estrogen.

And, once body fat drops below a certain percentage (around 11%), the reproductive system goes on sabbatical. Menses generally cease, and the desire for sex is replaced by a desire for one of those Vyper 2.0 vibrating foam rollers, which, sadly, these women will probably use only for therapeutic purposes.

But there’s another factor, this one a musculoskeletal one, that can affect a chronic female overtrainer’s sex life – the pelvic floor. Sometimes after childbirth, a woman can experience a loosening or slackening of what Women’s Health described as a “hammock” of muscles. This loosening can make sex less pleasurable, especially if her partner’s girth comes nowhere near approximating that of a fireplug.

Conversely, training too much can cause the pelvic floor to over-tighten. As mentioned above, it’s called “hypertonicity,” and it can make sex painful. Normally, the vagina is designed to stretch when something is inserted into it, but if there’s no give (as seen in cases of hypertonicity), the brain interprets it as pain.

Tight muscles elsewhere compound the problem. According to leading pelvic floor physiotherapist Julia Di Paolo, as quoted in Women’s Health, “Tight calves can pull down on your hamstrings, tilting your pelvis and tightening the floor. It’s why maintaining a groin prepped for good times is no longer simply about teaching the right muscles to contract but also learning to relax them. We call it down training or reverse Kegel.”

Di Paolo explains that these women should imagine picking up a blueberry with their vagina and anus as they exhale and then fully letting the blueberry drop as they exhale.

Okay then.

Once the pelvic floor starts to loosen, presumably through a combination of down training the body and the pelvic floor, sexual pleasure increases.

What Should We Do About Exercise-Related Libido Problems?

If your libido is suffering as a result of too much (and too intense exercise), the most obvious solution is to take it down a notch. Dr. Hackney reminds us that exercise increases libido up to a point, but train beyond that point often enough, and you’ll experience a drop in libido. He calls it the “inverted U.”

A general rule of thumb, at least according to the people who study such things, is to limit the real high-intensity, full-fledged CrossFit stuff to maybe three times a week. You might also consider taking a week off to reset the hypothalamic/pituitary axis, but that’s probably like telling a two-pack-a-day smoker to lay off the smokes for a week.

Alternately, there are probably things you can do to at least ameliorate the libido-lowering effects of obsessive overtraining. There’s sleep and good nutrition, which should be painfully obvious.

Men might also consider a testosterone booster like Alpha Male (on Amazon). It’s not as powerful as true testosterone replacement therapy (TRT), but it’ll give most males a decent boost in T levels.

Both men and women could also try a workout formula like Surge Workout Fuel (on Amazon), which, among a long list of workout-potentiating things, decreases stress hormone levels following exercise.

Finally, men and women should consider taking P-Well (on Amazon), our all-around supplement for vascular sexual health and functioning.


Regardless, it all comes down to making a decision about whether the obsessive pursuit of some hazily defined definition of physical perfection is worth being a walking contradiction: a body seemingly built for sex but is mentally and, to a point, physically, neutered.




  1. Hackney AC et al. Endurance Exercise Training and Male Sexual Libido. Med Sci Sports Exerc. 2017 Jul;49(7):1383-1388. PubMed.
  2. Lost Your Sex Drive? Why Fitness Lowers Libido. Women’s Health. 01/15/2018.
  3. Ahtianinen JP et al. Heavy resistance training and skeletal muscle androgen receptor expression in younger and older men. Steroids. 2011 Jan;76(1-2):183-92. PubMed.

Yes on this. This is something that was historically true with endurance athletes like triathletes that put in hours of training each day. Low T and no libido. But, this is true of any type of excessive training efforts. Short, intense workouts a few times a week are great. But turn every training session into a grueling, all-out effort and your hormones and T-levels will suffer.