Last longer and train harder: Foc.us on endurance
When it comes to sport, we all want to get better, right? Stronger, faster, fitter, leaner. And we all know that to get better, we have to push beyond our current limits. If you don't push hard enough, you'll never improve.
When athletes train to get stronger, they gradually increase the stress they place on their bodies. Doing it gradually gives their body a chance to adapt. This is the principle of progressive overload which has been the basis of all physical training since it was first developed by Dr Thomas Delorme between 1945 and 1951. Delorme was an orthopaedic surgeon working on the rehabilitation of soldiers injured in the Second World War. He was concerned specifically with developing a method to gradually increase physical strength, but this principle is at the heart of all physical training and one that is now very familiar.
We all know we can't go from being a couch potato to a marathon runner without building it up slowly over time. We have to train regularly, pushing ourselves that little bit further each time -- and that's the key to progress: to push yourself each time.
Push yourself to get stronger
Easier said than done, you might say. And you'd be right! It's not always easy to find the drive and determination. After a hard, stressful day at work, the last thing you may feel like doing is pushing yourself beyond your limits.
Well, you wouldn't be alone. Research shows that mental fatigue has a significant impact on physical performance. In one study, scientists found that when participants were given hard cognitive tasks to perform prior to exercise, their ability to push themselves dropped on average by 15%.
Sure, some people clearly push themselves all the time and have great levels of fitness and enviable physiques to show for it. Ever looked at athletes or fitness models and wondered how they find the motivation? Well, here's the truth: it is actually easier for them. They have nothing else to do! Most of their life revolves around their workout routines. They don't have all the conflicting stresses to cope with. Great for them.
The rest of us, however, need another plan.
You could hire yourself a personal trainer. Getting shouted at to complete one more rep can be an effective way of upping your motivation. Or you could try a running partner. Having someone to run against can provide a competitive edge which is also known to improve performance; unless of course, your running partner is even less motivated than you are!
The other alternative, that is taking the sporting world by storm, is brain stimulation. It's cheap and effective, and allows you to compete against yourself. It has already been used by many pro-athletes at the Rio Olympic games and has a large body of supporting scientific literature to back up its claims.
Let's be honest, this is performance enhancement. But it's not the same as a drug. It doesn't have all the side-effects associated with drugs. Drugs flood your body with chemicals that interact with your entire physiology in complex ways that are not always well understood. The negative impacts can be severe, which is the reason they are not usually recommended.
By contrast, brain stimulation is proving to be a far simpler intervention. It is by no means fully understood and there may still be side-effect that we are not yet entirely aware of, so you should always stick within currently tested parameters. But brain stimulation doesn't impact your entire body in the way that pharmacological substances do. So many scientists have become very optimistic that such neurological interventions could herald a promising alternative methodology that is much safer than its chemical counterpart.
Nevertheless, you should certainly approach it with some caution and be sure to follow the right protocols. Most scientists and clinicians would always recommend that athletes (amateur or pro) follow the science as closely as possible. The science is by no means without controversy, but it's a good place to start and gives you the security of knowing that it has some independent evidence to support the claims.
Foc.us on endurance
In my previous blog post, I described how to use the Foc.us tDCS brain stimulator to accelerate explicit motor skill learning, facilitate implicit motor skill learning and to get into the zone when you need to compete. In this post, I'm going to describe how the same equipment can be used to extend your endurance and help you push yourself that little bit further.
The Foc.us devices are by no means the only tDCS devices on the market, though they were one of the first that were widely available to the public. But they are, in my opinion, the best alternatives currently out there in terms of price and functionality. The truth, however, is that any stimulation device you think you can trust, will do just fine. The methodology I'm describing is based on science and not on any particular manufacturer.
Foc.us are currently selling a sports edition of their popular Go Flow tDCS stimulator. It contains everything you need to follow the protocols in this post. You won't absolutely need it, but it will make things easier.
So let's get on with it.
Brain stimulation and endurance
There are two approaches which scientists have discovered may have an effect on endurance. One approach seeks to impact your perception of how much you've exerted yourself. In a way, it resets your fatigue levels, so you are able to exert yourself for longer without experiencing the levels of fatigue which would result in you feeling too exhausted to continue. The second approach acts like a pain killer, reducing your perception of the pain that is associated with the build up of fatigue and thereby letting you push harder. It's an approach that has actually been highly effective as an anti-depressant, but has recently been shown to have an affect on physical endurance.
Neither of these are guaranteed to work. Brain stimulation just isn't that well developed yet. The studies so far are small and results have oftentimes not been replicated; or worse still, have been contradicted altogether. So these are protocols for you to try, not protocols guaranteed to succeed. We're all individuals, things that might work for me, may not work for you. The thing to do is to proceed gradually and cautiously and see what, if anything, fits your needs.
We won't delve deeply into the science but we'll touch on enough to give you a basic idea of how and why the method might be working. If you'd rather just know what to do, you can skip straight to the "trying it for yourself" sections that follows both explanations.
Training for longer: delaying the onset fatigue
Why do we get tired and stop exercising?
All physical exertion puts the body into what scientists and clinicians call a catabolic state. This state is essentially destructive. Energy stores in the body are broken down and depleted. A prolonged catabolic state leads to rising levels of pain and fatigue until eventually our endurance threshold is reached and we stop. The body instinctively pushes back into what's called an anabolic state in which it repairs itself and replenishes energy stores.
The exact mechanisms involved are still not understood, but it has become increasingly clear in the last two decades that the brain plays a central role in governing our levels of physical output and how long we can maintain it. It's not all down to how well your heart and muscles can perform.
This might sound obvious now, but it wasn't always. Since the 1920s, clinicians were taught that endurance was entirely a function of cardiovascular output thresholds -- meaning: your endurance levels were dictated entirely by how much blood and oxygen your heart could pump around your body.
It's only recently that scientists have begun to recognise that the brain plays a central role in regulating physical performance based on the feedback it receives from the body's sensory systems and from it's own psychological state. How your brain interprets and responds to the feedback it gets from the body has a major impact on your levels of performance.
Part of the feedback and control mechanism is a network of nerves called the Autonomic Nervous System (ANS), which itself is made up of two branches. The sympathetic branch of the ANS is responsible for the well known 'fight-or-flight' response. In times of stress it will trigger an increase in heart rate and blood pressure and activate the thyroid and adrenal glands to produce hormones crucial in the production of energy. This is the catobolic arm of the ANS -- responsible for tearing down the body in response to immediate needs. In contrast, the parasympathetic branch of the ANS is anabolic and attempts to promote homeostasis of the body, keeping it in equilibrium during times of rest and recuperation. It is less often known about, but is sometimes referred to as the "rest-and-digest" response of the body. Crucially, it is also the state your body prefers to be in.
These two halves of the ANS work together; speeding us up for action and slowing us down for rest. The longer you spend in a catobolic state, the stronger the response from the parasympathetic system as it tries to return your body to its preferred anabolic state of rest and repair. Athletic endurance is known to be associated with the delaying of parasympathetic withdrawal. As athletes become fitter, they are able to delay the onset of parasympathetic dominance and the consequent slowing of energy production that it entails.
Of course, the ANS is called autonomic for a reason -- it acts autonomously. This is why we don't need to think to breath in and out or to increase our heart rate when we run. But as autonomous as it is, its function can also be highly regulated by the brain.
That's why mood can effect the functioning of the ANS and why your physical performance can vary independently of your actual physical fitness or current levels of tiredness. For example, in one study, scientists were able to use hypnosis to extend the endurance of subjects by altering ANS function.
The upshot of all this is that if you are in the right frame of mind, you can train for longer, run that extra mile or climb that extra hill. If you're in the wrong frame of mind, you might quit too early, thereby failing to give yourself a proper workout or failing to beat your current personal best.
So how can brain stimulation help here? Well, OK, there isn't any one single part of your brain that's entirely responsible for governing ANS response. But two regions are know to play very significant roles: the temporal cortex and the insular cortex. In one stimulation study, scientist reasoned that stimulating this region could delay the onset of parasympathetic withdrawal. They took trained cyclists and administered 20 minutes of anodal stimulation to the temporal cortex, then gave the participants a cycling exercise test. Participants were required to keep cycling against an increasing resistance until they felt too tired to continue. Cyclists who received the stimulation increased their overall exercise intensity by approximately 4% while reporting a slower onset of fatigue.
That may not sound like much - and it isn't. But it may be just enough to ensure that you are pushing yourself that little bit further each time. And that's really all you need to do to keep improving.
Trying it for yourself
To try this out, we need to stimulate the left temporal and insular cortices.
Finding your left temporal cortex is pretty easy. It's situated just above your left ear. The insular cortex is deeper in your brain but in approximately the same location. If you have the Go Flow Sports edition cap, simply place the electrode in the pre-marked hole and line up the cap as per the instructions.
The left temporal cortex is marked as T3 under the 10/20 system of electrode placement. So if you don't have the cap, you can still locate the correct spot without too much difficulty. Check here for a 3D visual guide that could help.
The anode (+ve) should be placed over the left temporal cortex at T3 (above the left ear) and the cathode (-ve) over the contralateral (right) shoulder.
Stimulate at 2mA for 20 minutes just before starting your workout or competition. If there's some time between stimulation and working out, don't worry too much, but try to keep the delay to a minimum. See my earlier post for more explanation on how to go about preparing your kit.
And that's it.
As always, be sure not to overdo it. See the end of this post or my earlier post for some safety guidelines.
Training harder: handling the pain
One of the reasons we stop exercising is because it hurts. Unfortunately, as we know, we have to push through some of that pain to makes improvement gains. This is the basis of our second approach: to alter our perception of the associated pain so that we can push that little bit harder.
All that said, ignoring serious pain altogether can of course result in injury. So it's important to know the difference between exercise induced pain, and pain that could signal bodily damage.
The pain we feel from exercising is actually a side-effect of energy production under high demand and recedes far more quickly than the pain we feel from getting genuinely hurt.
As we exercise, the energy demands of our muscles are initially met via a process called aerobic glycolysis -- often referred to simply as aerobic respiration. This is generally not associated with pain. Oxygen is inhaled and combined with glucose stored in our muscles and liver to produce energy, with carbon dioxide and water being produced as by-products. The carbon dioxide and a lot of the water is then exhaled and the energy is used to drive our muscles.
But as we push ourselves harder, our muscles demand more energy and aerobic glycolysis alone can't keep up with demand because we cannot breath in oxygen fast enough. So the body responds by supplementing energy production via anaerobic glycolysis. This process doesn't even require you to breath as it utilises no oxygen at all; instead the glucose is broken down directly to form energy. But the process is less efficient and results in a by-product called lactate. It is this lactate production that increases the acidity of the muscle tissue and this rise in acidity is what we feel as a gradually increasing burning sensation.
Lactate is flushed from our muscles quite rapidly via our bloodstream, so when we stop exercising, the burning sensation quickly recedes. This is in strong contrast to the sharp stabbing pains we feel from sudden tissue damage.
Marathon runners mainly work within their aerobic threshold but sprinters work well beyond it. This is why sprinting hurts far more quickly than jogging does. Being able to handle this pain better is going to have a significant impact on how hard you can push yourself.
Studies show that athletes are better able to cope with pain than non-athletes and this allows them to train harder. To push themselves harder, athletes often develop cognitive strategies that allow them to do this. And in turn, training harder stimulates the body to improve its rates of both aerobic and anaerobic energy production, making you fitter and stronger.
Cognitive pain modulation
The perception of pain is highly dependent on individual beliefs and attitudes towards the pain and its causes. Brain imaging studies have shown that when pain signals are received along nerve fibres, the neural pathways engaged in the processing of that pain are highly cognitive. What this means is that the parts of your brain more associated with thought and decision making are also highly engaged during the subjective feeling of pain.
Most of your conscious decision making occurs in a part of the brain called the prefrontal cortex - situated, as the name suggests, at the front of your head. It is one of the latter evolutionary developments of the mammalian brain and we humans have a particularly well developed one. One of the most active regions of the frontal cortex during pain processing is called the dorsolateral prefrontal cortex (DLPFC).
Studies have shown that stimulation of the DLPFC can modulate pain, changing the way it is perceived and increasing our tolerance to it. For example, in a recent study, researchers investigating the affects of tDCS on multiple sclerosis sufferers, administered anodal stimulation over the left DLPFC and found that their patients were able to cope with the pain much better.
The stimulation doesn't work in the same way as pharmacological analgesics do. Paracetamol for example is thought to block the pain signals themselves as they pass along the spinal cord, just before they enter the brain. So the brain has little idea the pain is occurring at all. In contrast, stimulation of the DLPFC doesn't block the sensations, but rather modulates the person's emotional response to the pain, allowing them to process it in less negative ways. This could be likened to the cognitive coping mechanism developed by more advanced athletes.
Consequently, some researchers have postulated that the stimulation of DLPFC could help in pain processing -- thereby allowing athletes to train harder. In a recent Horizon episode which aired on the BBC, researchers tested this idea on two cyclist who were twin brothers and found that stimulation of one brother's DLPFC just before a cycling test was able to significantly boost his performance.
Trying it for yourself
To try it, place your anode (+ve) over F3 (your left DLPFC under the 10/20 system) and your cathode (-ve) over your contralateral (right) shoulder. Then stimulate for 20 minutes at 2mA before training or competing.
You can approximate the location of F3 by placing fingers from both your hands on either side of the temples of your head (left fingers on left temple, right fingers on right temple), then sliding them up about 20 degrees into your hairline and about a finger's width backwards; your left finger will then be roughly over F3. However, the truth is that this will be quite inaccurate.
If you have a Foc.us cap (either the sports cap or the full electrode placement cap), you can easily find the the correct position. If you don't have a Foc.us cap, we wouldn't actually recommend approximating F3, even using the method above. It's better to take accurate measurements (using a tape measure) - we will cover how to do this in future posts. In the meantime if you would prefer not to use a Foc.us cap, there are alternative caps and straps on the market. We would genuinely recommend you get one of them.
I can't really say enough about safety. After all, this is your brain you're dealing with. All Foc.us equipment will come with appropriate warnings on usage and on who should avoid it altogether. You can also see the end of my earlier post for more guidelines. But the basics of safety are pretty obvious:
Don't combine brain stimulation with drugs or alcohol. If you have any neurological conditions, we recommend you don't try it, but you can always consult your doctor.
Don't overdo it. At Foc.us, we like to recommend that people leave 48 hours between stimulation sessions. You'll read studies in which stimulation occurred daily, and scientists are beginning to look at protocols that require this level of frequency, but it will depend a lot on the specific protocols and the goals of the researchers. The researchers may have been interested in investigating a particular neurological phenomenon which required frequent stimulation. But if you want to use brain stimulation in the long run, it's best to give your brain a chance to recover between stimulation sessions, much like you would with any training: your body needs time off and so does your brain.
Stick within the parameters of independent studies and to currents and durations that you are personally comfortable with. If you do experience any discomfort during stimulation, discontinue it immediately -- the 'no pain, no gain' mantra does not apply here! Always discontinue a session using the shutdown switch on your device because ripping electrodes off can cause current spikes. If you're using the Go Flow, simply pressing the rocker button will ramp down (gradually terminate) the current. With the Foc.us V2, you can simply give it a shake. If your device doesn't have such a feature, get one that does!
The good news is that this sort of mild brain stimulation has actually been shown to be generally very well tolerated and extremely safe - provided you stick within the known parameters. If you do that, you should be fine.
That's it for now. Be safe and happy stimming!