Thursday, August 20, 2015

Brain Doping and Improved Performance

Even Phil and Paul have stopped using the phrase "lactic acid" to describe fatigue, I noticed. About time, too, because the central governor theory of fatigue seems to have finally gained won out. That theory, you'll remember, says that fatigue is a mental effect. The brain imposes it on the body to protect it from damaging itself. When we feel burning in our legs, that sensation is just our brain telling our legs to hurt, roughly.

Training, say books like Matt Fitzgerald's Brain Training for Runners and Tim Noakes' Lore of Running, is mostly brain training.  That's because (thankfully) our brains are conservative; we could push ourselves a whole lot more than we do without actually hurting ourselves. So when we train, we're mostly teaching our brains to allow our bodies a few more liberties.

Think about that.

Noakes and Fitzgerald emphasize that it's not a voluntary thing. It's not a matter of will power.

That's their story, in any case.

My response has been, "well, then, why didn't Lance use Ritalin instead of EPO?" If his brain was the limiter, why didn't he dope it rather than his blood?

Noakes and Fitzgerald have an answer for this. They point to the testimony of athletes who have doped, guys like Tyler Hamilton, who insist that blood doping often doesn't really make it easier to ride faster. Often, so goes this theory, it took a while for doped riders' brains to realize that their engine had, with an injection of EPO or an infusion of red blood cells, expanded. 

This is one theory about why so many riders suffer the day after rest days; i.e., their brains fail to accommodate the blood infusion.

The other possibility is that the central governor theory is wrong--maybe fatigue is caused by something physical. Maybe fatigue isn't just something my brain does to me. It certainly feels like the pain is coming from my lungs, my legs, my muscles--everywhere, in fact, except my brain!

Enter today's headline: Smart Drug Modafinil Actually Works (smart in that it makes us smart; not that it is somehow a smart in the say a smart car or a smart watch is touted to be).  

Researchers found that the the drug seems to improve "higher-brain functions that rely on contribution from multiple simple cognitive processes." It improved attention, learning, and executive function--sifting through plans and making decisions. It didn't improve creativity, multi-tasking, or memory.

Basketball, baseball, football, and the like--it's clear why athletes in those sports have been drawn to modafinil, since those sports require smart, quick executive decisions (e.g., whether to make dangerous pass). 

If fatigue is just lactic acid, it's unclear why modafinil might benefit endurance athletes.

On the other hand, if you accept the central governor theory, it's clear how it works: it works on the brain's governor. Here's what a 2004 study found:
"Acute ingestion of modafinil prolonged exercise time to exhaustion at 85% VO2max and redouced RPE. The RPE results suggest that the dampening of the sensation of fatigue was likely a factor responsible for the enhanced performance."
In other words, modafinil makes people faster for longer by changing the brain's workings--researchers did not see any physiological signs that modafinil impacted the blood or muscles or heart; it did change RPE. Things just felt easier. There was less fatigue.

Modafinil has been a banned substance for over a decade now, and many athletes, including Barry Bonds and professional WNBA athlete Diana Taurisi, have been connected with it. It has been less common in cycling; masters racer Todd Robertson was busted for it in 2014--his second doping offense.   

Painkillers, like modafinil, reduce fatigue by altering the brain's central governor. Even mild, over-the-counter painkillers like acetaminophen (e.g., Tylenol) have been shown to improve performance.The mechanism for improved performance is the same as with modafinil: increased power at lower perceived rate of exertion. When you're on painkillers and riding a bike, it does get easier and you do go faster. In the words of the researchers:
"Using acetaminophen, participants cycled at a higher mean PO [power output], with an increased HR and B[Lactic acid], but without changes in perceived pain or exertion. Consequently, completion time was significantly faster. These findings support the notion that exercise is regulated by pain perception, and increased pain tolerance can improve exercise capacity."
The effect in that study on acetaminophen is surprisingly significant: 500mg of acetaminophen is correlated with going 30 seconds faster in a ten-mile time trial.

If 500mg of acetaminophen gets you a minute over 40k, what does a nice pill of tramadol--Sky's late bottle filler of choice--get you? Unfortunately, there is very little research on it. I couldn't find anything on tramadol and cycling performance.

The takeaway, for those of us who don't want to use painkillers, is awareness of what's happening when we train. The largest effect of riding hard is on our brain.

Being away from racing and training hard and trying to come back makes this clear. I'm not a whole let heavier than I was when I was fit, and my threshold isn't too far below what it was. What I'm lacking is at the top end--that ability to cruise on climbs and when there's a surge. The sensation of straining at my limits feels crushing. Somehow, when I was fit, it never really did. There was a greater flexibility at the edge of my fatigue where I often felt as though I could just keep going harder.

There are certainly some corporeal elements to fatigue, but as this research and these effective brain drugs show, there is also certainly a mental one.

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