Sympathetic and parasympathetic type of overtraining

Overtraining, in general, is excessive frequency, duration, volume, or intensity of training causing the body’s inability to recover and adapt. There are two types of chronic overtraining: sympathetic and parasympathetic. If we can better understand the differences between them, then we can select the most appropriate recovery modality. Sympathetic and parasympathetic is referring to autonomic nervous system branches:


Their functions are:


The Sympathetic Nervous System (SNS) controls the fight-or-flight response, so is active during stressful situations like training and/or competition. During fight-or-flight, the body is releasing hormones like cortisol, epinephrine (adrenaline), and norepinephrine. Epinephrine’s job is to increase heart rate during periods of stress, he also constricts blood vessels which elevates blood pressure and helps to get blood to the muscles. Cortisol is responsible for increasing blood sugar in the body to provide readily available and fast-burning fuel. During fight-or-flight cortisol also suppresses the immune system and helps in fat metabolism.
Sympathetic overtraining (SO) is connected with high amounts of anaerobic activity and in general, is happening in sports where anaerobic energy mechanism is dominant – examples are MMA, boxing, basketball, American football, tennis, and short distances in athletics. SO refers to an OVERACTIVE sympathetic nervous system producing TOO MANY STRESS HORMONES. This is typically happening when high volumes of work are done around the lactate threshold, without adequate recovery between sessions and during a prolonged period of time. This type of overtraining is characterized by restlessness, disturbed sleep, weight loss, accelerated resting heart rate and delayed recovery. So-called parasympathetic recovery techniques are the best way to combat against it – meditation, massage, hot tubs, deep water floating, taking a nap during the day. Active recovery methods such as light intensity resistance training or low-intensity cardio training can be beneficial as well. Athletes should avoid taking any form of stimulants during this period – caffeine for example.

The Parasympathetic Nervous System (PNS) controls “rest and digest” hormones during a period of recovery after the stress is over. It works mostly by inhibiting uptake of hormones involved in fight-or-flight responses such as epinephrine and cortisol. Parasympathetic overtraining (PO) is associated with high volumes of aerobic activity – examples are long-distance running and rowing, Nordic skiing, bicycling. Symptoms of PO include depression and decreased heart rate, feeling of fatigue and decreased performance. In this scenario, you should include so-called sympathetic recovery techniques. Recovery program should include electric muscle stimulation (EMS), cryotherapy, contrast baths, saunas, or cold water swimming.

Both forms of overtraining involve malfunction of the Sympathetic Nervous System. In the state of Sympathetic Overtraining, the SNS is overactive, producing too many stress hormones that keep us in the “emergency” or “fight or flight” state all the time. On the other hand in Parasympathetic Overtraining the SNS is underactive or “fatigued” and unable to produce the necessary hormones to enter in the “fighting” mode.


These are considerations when we are dealing with overtraining symptoms but these are guidelines about how we need to approach recovery modalities with different types of athletes even when the athlete is not in overtraining state. And this is what my objective with this article was all about. What I want to explain is that we need to take into consideration what kind of athlete is standing in front of us before we decide about after session recovery modalities.

If we prescribe ice bath for the athlete who is always in the “on” mode (read SNS dominant) – hyperactive, easy get nervous but difficult to relax, naturally fast and explosive – we are doing more harm than good!


Ice baths stimulate even more SNS activation (production of stress hormones). Even when you look at this photo and imagine yourself entering into this tub you can feel adrenaline spike inside your body! Any kind of “aggressive on the autonomic nervous system” technique will postpone the period when this athlete will finally enter into recovery mode. If we really want to speed up the recovery process for that athlete we need to introduce parasympathetic recovery techniques, where we want to calm down his nervous system!

Before we decide what to do for recovery we need to look at a big picture. Ask yourself questions like what kind of athlete we have from neurological standpoint (more SNS or PNS type of athlete), from what kind of activity we want to recover (running or weight lifting in the gym), when is next training session (same day or 24 hours later), HRV (heart rate variability) value last few days, training phase (GPP or SPP), etc.… Answering on all of this questions will help us decide about recovery approach.