FUELLING THE WORLD’S LONGEST NON-STOP SWIM

How far can a human swim non-stop? No sleep, no rest and no touching land. On June 16, 2024, we wanted to find out and embarked on a 510km (317 mile) non-stop swim down the Yukon River (Canada) in water temperatures as low as 8°C (46.4°F). Now ratified as an Official Guinness World Record, the full documentary of the swim can be seen on YouTube but it’s important to note the entire adventure was only made possible by science-backed support we had from the nutritional ninjas that PhD HQ! But there was also another record set that day. An unofficial, accidental record. One that I do NOT advocate anyone try, but one that was crucial to the success of the swim. That record? Caffeine consumption in the form of blue-gummy-bear flavoured CHARGE pre-workout. Now obviously the Yukon swim was a very specific (and unique) type of endurance event and one I (again) wouldn’t recommend to anyone, but embarking upon this adventure did teach me a lot about caffeine and those lessons I’d like to share with you now.

CAFFEINE USE: NORMAL ‘EVERYDAY’

According to the U.S. Food and Drug Administration (FDA) and other health organizations, up to 400milligrams (mg) of caffeine per day, which is roughly the amount in four 8-ounce cups of brewed coffee, is safe for the majority of people under normal circumstances. Of course, intake will vary significantly based on factors such as age, body weight and overall health, but it’s fair to say that a 56-hour, 510km (317 mile) swim down the Yukon river does not constitute “normal circumstances” which is why I had to look to the Tour De France cyclists, ultra-marathon runners, legends from long-distance swimming and friends in the military to help and this is what I found.

CAFFEINE USE: ENDURANCE ATHLETES

Considered to be the most widely consumed psychoactive drug in the world, it’s a central nervous system (CNS) stimulant that I used after speaking to friends in the U.S Navy Seals who took part in a study that monitored the effects of caffeine on cognitive (mental) performance and mood during 72 hours of sleep deprivation.[1] They were Navy Sea-Air-Land (SEAL) trainees at the time and volunteered to receive either 100, 200, or 300 mg caffeine or placebo in capsule form after 72 h of sleep deprivation and continuous exposure to other stressors as they performed memory tasks and reaction time tests[2].

What the researchers discovered was, “Caffeine mitigated many adverse effects of exposure to multiple stressors. Caffeine (200 and 300 mg) significantly improved visual vigilance, choice reaction time, repeated acquisition, self-reported fatigue and sleepiness with the greatest effects on tests of vigilance, reaction time, and alertness.” This lead them to conclude, “Even in the most adverse circumstances, moderate doses of caffeine can improve cognitive function, including vigilance, learning, memory, and mood state. When cognitive performance is critical and must be maintained during exposure to severe stress, administration of caffeine may provide a significant advantage. A dose of 200 mg appears to be optimal under such conditions”.

Based on these findings I decided to supplement the swim with caffeine for the following 3 reasons:

1. TO COMBAT MY CIRCADIAN RHYTHM

I used caffeine (PhD Charge) to try and ‘override’ the rise in melatonin, desire to sleep and essentially ‘bio hack’ the circadian rhythm (the body’s 24 hour biological clock). This was based on numerous studies[3] that found caffeine[4] supplementation can, “Reverse changes in alertness and mood produced by prolonged sleep deprivation.”[5]

2. TO IMPROVE PERFORMANCE

I also used PhD charge during the swim when I needed to sprint either across or against a counter current caused by the river. Why? Because it’s one of the most widely used ergogenic aids (performance enhancing supplements) permitted by the International Olympic Committee since it’s been found to, “permit the athlete to train at a greater power output and/or to train longer and has also been shown to increase speed and/or power output in simulated race conditions.”[6] Worth noting is this was across many studies[7], multiple sports[8] and over various intensities[9] and distances[10] and all because of the following mechanisms scientists have proposed when researching caffeine and its performance enhancing properties[11].

• Serve as an ‘adenosine blocker’. Adenosine is one of the body’s more powerful molecules and builds up in the bloodstream during exercise (due to the breakdown of Adenosine Tri-Phosphate which is the molecular energy of the muscles). This in turn inhibits neural activity, causes drowsiness and essentially tells our body to rest, recovery and rebuild our energy reserves. But caffeine was found to attach itself to the same receptors that adenosine would normally latch onto, (hence the term ‘adenosine blocker’) which then reduces adenosines-induced drowsiness. Basically, caffeine serves to lift your foot off the ‘biochemical break’ of the body that is caused by the increase in adenosine. Helping you (in theory) to train harder and longer.
• Increase Your Power Output: Research from the Journal of Medicine and Science in Sport and Exercise[12]found caffeine, even when taken in low doses can improve your power. This is because the study served to analyse cycling power output and found that a dosage of 3mg/kg increased power by up to 3.5% when compared to a placebo group. Granted this might not sound like a lot, but it could be responsible for the new one rep max you put up on the bench press.
• Improve the “ionic environment” within the muscle: Research conducted at the University of Guelph in Ontario, Canada[13] found that caffeine supplementation could ‘permit an athlete to train at a greater power output and/or to train longer by producing a more favourable ionic environment within the active muscle.’ It’s believed it does this by increasing levels of intracellular calcium in skeletal muscle which (in turn) makes the muscles contract more efficiently by improving something called ‘excitation-contraction coupling’. This is the sequence of events through which the nerve fibre stimulates the skeletal muscle fibre causing its contraction.

3. TO REDUCE PERCEPTION TO PAIN

Numerous studies[14] have shown that caffeine is capable of decreasing pain[15] and perceived level of exertion[16] especially in endurance athletes. This is because as well as serving as an ‘adenosine blocker’, it also enables excitatory neurotransmitters (chemical signals in the brain) such as dopamine, acetylcholine and serotonin to move about more freely and stimulate the brain and therefore ‘overrides’ feelings of discomfort.[17] This why researchers from  the Department of Clinical Neurosciences at Oxford University concluded, “The addition of caffeine (≥ 100 mg) provides a small but important increase in the proportion of participants who experience a good level of pain relief.”[18]

CAFFEINE: DOSAGE  

It’s often cited that for events lasting 0 to 5 hours, 3-6 milligrams of caffeine per kilogram (1.4-2.7mg per lb) of bodyweight is ideal to bring about the previously mentioned physiological (and psychological) response. For a 70 kg (154 lb) runner, this translates to 210-420 mg of caffeine. But during longer duration events this recommendation may start to become less useful. This is because the guidelines don’t account for these very long durations when you may completely metabolise the caffeine you consumed pre-race and during the early stages. Here larger dosages are required and can easily exceed 3-6mg per kilogram of bodyweight. For example, Damian Hall consumed a total of 1,390mg over the 52 hours and 35 minutes he was racing during The Spine Race. This is an ultramarathon held over a distance of around 268 miles (431 km) from Edale, England, to Kirk Yetholm, Scotland, along the Pennine Way. As a slightly chunkier athlete than Damian (weighing 98kg on the start line of the Yukon swim) my total caffeine consumption for the swim was 1,900mg.  Again, a personal record but one I would not recommend you try, unless you too find yourself swimming down the Yukon River for 56 hours.

CAFFEINE: FINAL THOUGHTS

Very important to note is there are of course downsides to 56 hours of caffeine supplementation fused with severe sleep deprivation and I wouldn’t recommend it to anyone. This is because you’re basically causing an orchestra of biochemical reactions in the body in pursuit of a short-term goal, but it’s not sustainable. It’s like borrowing money from the bank, it’s great at the time but at some point, you will have to pay it back since no one can survive ‘biochemical bankruptcy’ for long. Which is why now back on land I’m prioritising sleep, rest and recovery and my PhD Shaker full of blue-gummy-bear flavoured CHARGE pre-workout has now been substituted for Super Greens, Diet Whey and Omega 3 for reasons I will explain in another article as I document my recovery.

[1] Lieberman, H.R., Tharion, W.J., Shukitt-Hale, B. et al. Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Psychopharmacology 164, 250–261

[2] Caffeine effects on marksmanship during high-stress military training with 72 hour sleep deprivation. William J. Tharion, Barbara Shukitt-Hale, Harris R. Lieberman Aviat Space Environ Med. 2003 Apr; 74(4): 309–314.

[3] Goldstein A, Warren R, Kaizer S (1965) Psychotropic effects of caffeine in man. I. Individual differences in sensitivity to caffeine-induced wakefulness. J Pharmacol Exp Ther 149:156–159

[4] Weiss B, Laties VG (1962) Enhancement of human performance by caffeine and the amphetamines. Pharmacol Rev 14:1–36

[5] Penetar, D., McCann, U., Thorne, D. et al. Caffeine reversal of sleep deprivation effects on alertness and mood. Psychopharmacology 112, 359–365 (1993).

[6] Graham, T.E. Caffeine and Exercise. Sports Med 31, 785–807 (2001).

[7] Ivy, John & Kammer, Lynne & Ding, Zhenping & Wang, Bei & Bernard, Jeffrey & Liao, Yi-Hung & Hwang, Jungyun. (2009). Improved Cycling Time-Trial Performance After Ingestion of a Caffeine Energy Drink. International journal of sport nutrition and exercise metabolism. 19. 61-78. 10.1123/ijsnem.19.1.61.

[8] STUART, GENE R.1; HOPKINS, WILL G.1; COOK, CHRISTIAN2; CAIRNS, SIMEON P.1 Multiple Effects of Caffeine on Simulated High-Intensity Team-Sport Performance, Medicine & Science in Sports & Exercise: November 2005 – Volume 37 – Issue 11 – p 1998-2005

[9] Berglund B, Hemmingsson P. Effects of caffeine ingestion on exercise performance at low and high altitudes in crosscountry skiers. International Journal of Sports Medicine 3: 234–236, 1982

[10] Essig D, Costili DL, VanHandel PJ. Effects of caffeine ingestion on utilization of muscle glycogen and lipid during leg ergometer cycling. International Journal of Sports Medicine 1: 86–90, 1980

[11] Lopes JM, Aubier M, Jardim J, Aranda JV, Maclen PT. Effect of caffeine on skeletal muscle function before and after fatigue. Journal of Applied Physiology 54: 1303–1305, 1983

[12] Lane SC, Areta JL, Bird SR, Coffey VG, Burke LM, Desbrow B, Karagounis LG, Hawley JA (2013) “Caffeine ingestion and cycling power output in a low or normal muscle glycogen state.” Journal of Medicine and Science in Sport and Exercise, 2013 Aug;45(8):1577-84.

[13] Graham TE (2001) “Caffeine and exercise: metabolism, endurance and performance” Sports Medicine. 2001;31(11):785-807.

[14] Baratloo A, Rouhipour A, Forouzanfar MM, Safari S, Amiri M, Negida A. The Role of Caffeine in Pain Management: A Brief Literature Review. Anesth Pain Med. 2016;6(3):e33193. Published 2016 Mar 26. doi:10.5812/aapm.33193

[15] Todd A. Astorino, Michael N. Terzi, Daniel W. Roberson, and Timothy R. Burnett (2011) International Journal of Sport Nutrition and Exercise Metabolism, 21, 2011, 27-32 © 2011 Human Kinetics, Inc.

[16] Duncan, Michael & Stanley, Michelle & Parkhouse, N. & Cook, K. & Smith, Mike. (2011). Acute caffeine ingestion enhances strength performance and reduces perceived exertion and muscle pain perception during resistance exercise. Eur J Sport Sci. 15. 1-8.

[17] Robert W Motl, Patrick J O’Connor and Rod KDishman (2003) “Effect of caffeine on perceptions of leg muscle pain during moderate intensity cycling exercise” The Journal of Pain Volume 4, Issue 6, August 2003, Pages 316-321

[18] Derry CJ, Derry S, Moore RA. Caffeine as an analgesic adjuvant for acute pain in adults. Cochrane Database Syst Rev. 2012 Mar 14;(3):CD009281.