JET LAG & HUMAN PERFORMANCE: How to Use Science To Outsmart Your Body Clock and Thrive Across Time Zones

By Dr. Mark Kovacs, PhD, FACSM
Human Performance Strategist, Wellness and Longevity Expert

​Jet lag isn’t just an inconvenience. For high performers, it's a scientifically measurable form of biological disruption. It impairs physical performance, slows reaction time, clouds mental sharpness, and affects hormonal and metabolic health. As someone who’s coached Olympic champions, advised global business leaders, and spent the last two decades immersed in the science of performance, I know one thing: jet lag must be taken seriously if we want to maximize durability, healthspan, and elite function across the lifespan. I have worked in multiple sports, but the three that have some of the most difficult travel schedules and jet lag plays a real impact is professional tennis, the NBA (Basketball) and the MLB (Baseball). Professional tennis players travel more than 100,000 miles per year and have some of the longest flights across the globe. The NBA and MLB also have a grueling travel schedule requiring over 50,000 miles per year and a lot of short trips with multiple circadian rhythm disruptions per week.
In this article, we’ll break down:

• What jet lag really is! From a circadian biology perspective
• Why it matters for performance, recovery, and long-term health
• The latest science on interventions that work (and those that don’t)
• Practical protocols you can apply before, during, and after travel
• How I use this information to help top performers adapt faster and perform better

Let’s begin by understanding the root of the problem.

What Is Jet Lag? The Circadian Desynchrony Dilemma
Jet lag is not just “feeling tired.” It’s a physiological mismatch between your internal circadian clock and the external time at your destination. Your body operates on a roughly 24-hour rhythm governed by the suprachiasmatic nucleus (SCN), which is a small region in the hypothalamus that synchronizes functions like sleep-wake cycles, hormone secretion, metabolism, and core body temperature. It is made up of 10,000 neurons and has a major impact on jet lag. I describe this as our bodies circadian clock.
When you rapidly cross multiple time zones, your internal circadian rhythm becomes misaligned with local time. This leads to:

• Sleep disturbances
• Daytime fatigue
• Cognitive slowing
• Mood disruptions
• Gastrointestinal discomfort
• Impaired physical performance

This phenomenon, formally termed circadian desynchrony, is more than a temporary nuisance; it can take days to fully resynchronize and significantly impact short-term performance and long-term health. These symptoms are a caused by a combination of factors that include: sleep loss, hypoxia, dehydration, low air pressure, confined seating and low humidity
Research shows the circadian system adapts better travelling east vs travelling west (Arendt, 2009). Some data has shown that if you do not put together a structured plan, crossing 6 time zones could impact your performance, health and enjoyment for 6-7 days (Arendt, 2009). Although some of the data shows that for each timezone crosses you may need 1 day for adjustment. So for a 6 hour time change you may need 6 days to fully adjust. This is assuming that you do not apply any of the strategies that we utilize to help individuals adjust.

---

​Why Jet Lag Matters for Durability and Healthspan
Chronic disruption of circadian rhythms has been linked to:

• Decreased athletic performance
• Altered cortisol and testosterone levels
• Increased inflammation and oxidative stress
• Impaired glucose metabolism and insulin sensitivity
• Higher risks of cardiometabolic disease, cancer, and mood disorders

In a high-performance context, whether preparing for a tournament in Tokyo or closing a deal in London, jet lag becomes a liability. For athletes, even a 1% reduction in reaction time or VO₂ max can determine a win or loss. For executives, decision fatigue and slower processing speed can affect outcomes and perception.
Our goal with the work we do with elite individuals and companies is to build resilient, high-functioning humans across all time zones and a significant aspect of our work is helping these high achievers manage jet lag with the latest science in a practical way.
 

​What the Latest Science Says: Interventions That Work
1. Light Exposure Timing
Light is the primary zeitgeber - an environmental cue that resets the circadian clock. Strategic exposure to natural or appropriate artificial light can shift your internal clock in the desired direction.
Exposure to bright light in the morning helps advance the clock (ideal for eastward travel), while evening light delays it (ideal for westward travel).
💡 Application:

• Eastward travel: Get 30–60 minutes of outdoor light early in the local morning. Avoid bright light in the evening.
• Westward travel: Delay morning light exposure. Maximize afternoon/evening light.

Specialty tools like light therapy glasses (10,000 lux) can enhance this process when natural light isn’t accessible.
Here is one cost-effective and small 10,000 lux (sun mimicking) lamp that works great for travel or home use - https://verilux.com/collections/happylight-therapy-lamps/products/happylight-mini
 
2. Melatonin Supplementation
Melatonin is the body’s “sleep hormone,” secreted by the pineal gland in response to darkness. Exogenous melatonin can shift circadian rhythms, especially when taken 4–6 hours before endogenous secretion begins.
A systematic review in the reputable Coachrane Database confirms that low-dose melatonin (~0.5–3 mg) taken at local bedtime at the destination can accelerate adaptation and improve sleep onset (Herxheimer et al 2002).
💊 Potential Application:

• Use 0.5–3 mg melatonin 1–2 hours before local bedtime for several days after arrival. Some athletes and high performers respond to higher doses of 4-8mg. However, higher doses should be under to care of a healthcare professional.
• Avoid higher doses unless specifically advised, as they can cause grogginess.
• Combine with dim lighting and blue-light blocking before bed.
• Caution: Some individuals do have mild side effects such as hypnotic effects, confusion, and headaches.

 
3. Timed Exercise
Exercise itself is a circadian cue. Moderate-intensity aerobic exercise in the morning advances the clock (east travel), while evening exercise delays it (west travel). Exercise timing significantly influenced how fast elite athletes adapted to transmeridian travel. This supports its role as a non-pharmacological intervention to shift rhythms (Thomas et al. 2020).
🏃 Application:

• East travel: 20–40 minutes of low-to-moderate intensity aerobic exercise (brisk walk, jog, cycle) in the morning.
• West travel: Same protocol in the early evening.
• Avoid high-intensity, high power type activity the first 48 hours post-arrival unless fully recovered (risk vs reward).

​

4. Sleep Banking and Strategic Napping
Travel-induced sleep debt is cumulative. Preemptively increasing total sleep time—called sleep banking—can blunt jet lag effects. Strategic naps (15–30 min) can also restore alertness.Also, pre-travel sleep extension improves alertness and performance post-travel, especially in athletes (Van Rensburg et al 2020).
😴 Application:

• Sleep 8–9 hours/night for 2–3 nights before departure.
• Upon arrival, avoid a nap on Day 1 and limit naps to less than 30 minutes on Day 2-4. Ensure the nap is before 3pm (local time).

5. Caffeine (Timed Use)
Caffeine is a double-edged sword. It can be very useful when timed correctly but disruptive if overused at the wrong time. Research shows it can improve alertness during circadian low points, but timing is critical.
In an in-depth review article by Halson et al (2019) caffeine taken at local morning (after red-eye flights) improved cognitive alertness and mood.
☕ Application:

• Use caffeine only after waking, not before or during red-eye flights.
• Dosing can be quit diverse based on genetics, tolerance, medical conditions etc. I have personally worked with individuals and have had varied dosages from 100mg to 500mg. It all depends on the individual circumstance -  personalization is the key.
• Avoid caffeine after 2:00 PM local time to protect evening sleep.

​

​6. Meal Timing and Nutrition
Your liver, gut, and pancreas all operate on circadian rhythms. Eating at inconsistent or inappropriate times can confuse peripheral clocks and exacerbate jet lag.
Fasting during travel and resuming meals at destination time may help resynchronize clocks, according to animal models and limited human trials.
🍽️ Application:

• Begin eating in sync with the destination's time zone upon arrival.
• Avoid large meals close to bedtime.
• Include protein-rich foods in the morning and limit sugar doe to insulin sensitivity and spikes in blood sugar.
• Hydrate well but avoid alcohol during travel—it worsens desynchrony.
• Caution: Limit sodium during the flight. Many airline meals are high sodium by nature. 

---

Technology and Innovation:
A number of technologies are available to help with the flight to improve sleep (if it is an overnight flight) and to also improve blood flow to limit stiffness in joints and muscles as well.
 
Sleep Aid Technologies
It is an exciting time with the advancements in wearable technologies that can impact Jet Lag and specifically improving air travel and sleep. A few different options exist due to rapid development of quality products. One product that I use with many high performers is a neurotech headband that is clinically shown to help people fall asleep significantly faster, and restart sleep fast if they wake up (Bressler et al 2024). This is non-invasive and easy to wear on the flight itself and also as a regular sleep aid to help individuals fall asleep faster in the new time zone (but is also great for regular sleep issues at home as well). I liked the product so much I became and advisor to them to help athletes and high performers in all industries get to sleep easier and get back to sleep faster if they awake during the night. Take a look here at Elemind -  
 ​

---

East vs. West Travel: What’s Harder to Adapt To?
Eastward travel shortens the circadian day (you have to go to bed earlier), which is biologically harder than westward travel (lengthening the day). This explains why a 9-hour shift to Europe can feel worse than a similar trip to Asia.
🧭 Key Takeaway:

• Prioritize light exposure and possible melatonin more aggressively for eastward travel.
• For westward travel, manage sleep extension, evening activity, and delayed meals.

Protocols I Use With Athletes and Executives
Based on two decades of experience with Olympic athletes, ATP/WTA players, NBA teams, MLB players and high-performing CEOs, here’s a practical framework I apply when helping individuals prepare for time zone shifts. Just remember that everyone is different and I spend a lot of time personalizing the recommendations for each individual based on genetics, blood work, travel schedule, environmental changes and individual preferences as well.  

✈️ Pre-Flight (2–3 Days Before Travel):

• Adjust bedtime 30–60 min/day toward destination time
• Begin melatonin or light therapy if crossing >6 time zones
• Increase total sleep (sleep banking). Add 30-60 minutes per day for 2-4 days before travel.
• Hydrate well and reduce alcohol

🛬 In-Flight:

• Set your watch to destination time upon boarding
• Avoid heavy meals and limit sodium; stay lightly active if possible
• Use blue-light-blocking glasses if flying overnight
• Consider fasting or time meals with arrival time
• Utilize blood flow enhancing technologies on the flight (heat, electrical stimulation etc) to reduce stiffness in joints and muscles.

🌞 Post-Arrival (First 3 Days):

• Morning light exposure if flying east; evening light if flying west
• Melatonin 1 hour before local bedtime (if recommended by your healthcare provider)
• Moderate and appropriate exercise at strategic times
• Avoid caffeine after mid-afternoon and
• Avoid napping during the day on arrival day and adjust as soon as possible to local time.
• On day 2 onwards keep naps short
• Eat meals based on local time, even if not hungry
• Look into the "caffeine nap protocol" that I utilize with many high performers - Read the article here

This approach has helped athletes win when matters most and executives perform on global stages with minimal lag.

Technology and Tools That Help
Here are evidence-supported tools I often recommend:

• Sleep Hardware – I am an advisor to Elemind and it is a great product 
• Electrical Muscle Stimulators for blood flow (MarcPro  & Firefly)
  • Marc Pro – I have worked with Marco Pro for more than a decade and here is a discount code - https://mark-kovacs.com/marc-pro.html
  • Firefly - a great product and have been utilizing these products for nearly a decade -  Click The Link Here  
• Re-Timer Glasses: Wearable light therapy for phase shifting
• Oura Ring / WHOOP / Garmin: Track sleep stages, HRV, readiness
• Blue-light blockers: Useful in-flight and before bedtime. Glasses to watch movies on the plane and also when watching tablets or your phone.
• Portable white noise machines: Aid sleep in new environments. These can be apps on your phone or portable (travel size machines). Many varieties exist. 

​Final Thoughts: Travel Durability Is About Rhythm
At its core, durability - the ability to perform at a high level for a long time - is intimately tied to rhythm. When we disrupt our internal rhythm through travel, we temporarily lose a degree of control over performance, health, and cognitive clarity. But we can reclaim it with the right strategies.
The most durable people I’ve coached (on the court and in the boardroom) don’t just adapt quickly. They plan ahead. They prioritize recovery. And they understand that every cell in the body keeps time - we just need to give it the right cues.
So the next time you travel, don’t wing it. Build a protocol, adjust your environment, and manage your body clock for sustained performance.
 
References

• Bressler, S., Neely, R., Yost, R.M. et al. A randomized controlled trial of alpha phase-locked auditory stimulation to treat symptoms of sleep onset insomnia. Sci Rep 14, 13039 (2024). https://doi.org/10.1038/s41598-024-63385-1
• Halson, S. L., Burke, L. M., & Pearce, J. (2019). Nutrition for Travel: From Jet lag To Catering. International Journal of Sport Nutrition and Exercise Metabolism, 29(2), 228-235. https://doi.org/10.1123/ijsnem.2018-0278
• Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. 2002;(2):CD001520. doi: 10.1002/14651858.CD001520. PMID: 12076414.
• Van Rensburg, D. C. C. J., Van Rensburg, A. J., Fowler, P., Fullagar, H., Stevens, D., Halson, S., ... & Cronje, T. (2020). How to manage travel fatigue and jet lag in athletes? A systematic review of interventions. British journal of sports medicine, 54(16), 960-968. https://bjsm.bmj.com/content/54/16/960
• Van Rensburg, D. C., Jansen van Rensburg, A., Fowler, P. M., Bender, A. M., Stevens, D., Sullivan, K. O., ... & Botha, T. (2021). Managing travel fatigue and jet lag in athletes: a review and consensus statement. Sports Medicine, 51(10), 2029-2050. https://link.springer.com/article/10.1007/s40279-021-01502-0
• Thomas JM, Kern PA, Bush HM, McQuerry KJ, Black WS, Clasey JL, Pendergast JS. Circadian rhythm phase shifts caused by timed exercise vary with chronotype. JCI Insight. 2020 Feb 13;5(3):e134270. doi: 10.1172/jci.insight.134270. PMID: 31895695; PMCID: PMC7098792.
• Tsukahara, Y., Kamada, H., Torii, S., & Yamasawa, F. (2024). Improvement of Jet Lag and Travel Fatigue Symptoms and Their Association with Prior International Travel Experience in Junior Athletes. Sports, 12(8), 220. https://doi.org/10.3390/sports12080220

 

If you have interest in learning more about the Durability program and working directly with Dr. Kovacs please see more information HERE