Sleep Is the Only Marginal Gain That Actually Matters

We spend thousands of dollars shedding grams off our bikes. We obsess over ceramic bearings, wax our chains, and scrutinize drag coefficients to save 4 watts at 25mph. Yet, most of us are simultaneously sabotaging the single most effective performance enhancer available to human physiology: sleep.

I work in big data for population health. I spend my days looking at what actually kills people versus what they think kills them. In the cycling world, we treat sleep like a bank account we can overdraw indefinitely to pay for early morning intervals. We assume that if we just "toughen up," we can cheat biology.

A new study out of Oregon Health & Science University (OHSU) just made it clear that we can’t. Biology always collects its debt.

The Data: A Population Health Reality Check

Researchers analyzed data from the CDC’s Behavioral Risk Factor Surveillance System (BRFSS) covering the years 2019 through 2025. This isn't a small n=12 study on college students; this is massive, county-level epidemiology covering the entire United States.

The study, published in Sleep Advances, looked at the correlation between insufficient sleep (defined as less than 7 hours) and life expectancy. The results were not subtle.

When controlling for the usual suspects—diet, exercise, social connection, and food insecurity—insufficient sleep was significantly negatively correlated with life expectancy.

Here is the statistic that should stop you in your tracks:

• In 2019, 84% of states showed a significant link between lack of sleep and early death.
• By 2024, that number hit 100%.
• In the 2025 data set, only three states didn't show a direct association between sleep insufficiency and lower life expectancy.

The researchers used mixed-effects modeling to isolate variables. They found that lack of sleep had a stronger relationship to life expectancy than physical inactivity. Let that sink in. From a purely mortality-risk perspective, being sedentary but well-rested might be statistically less dangerous than being an active cyclist who is perpetually sleep-deprived.

Only smoking and obesity showed a stronger correlation to reduced life expectancy than sleep deprivation. If you wouldn't smoke a pack a day because it ruins your VO2 max, you shouldn't be sleeping 5 hours a night.

The Mechanism of Action 🧠

As a PharmD, I look at interventions through the lens of "Mechanism of Action" (MOA)—how does the drug actually work in the body?

If we view exercise as a stimulus (the catabolic stressor), then sleep is the anabolic response (the repair). The study notes that insufficient sleep increases the risk for cardiometabolic disease and all-cause mortality.

When you sleep less than 7 hours, you are not just "tired." You are inducing a state of physiological inflammation. You are disrupting glucose metabolism, increasing cortisol, and impairing the clearance of metabolic waste products from the brain (the glymphatic system).

The study highlights that sleep health is a "modifiable health behavior." In clinical terms, this means it is a lever we can pull. Unlike genetic predisposition or past injuries, you have agency here. But the data suggests that missing this window doesn't just make you slow; it makes you statistically likely to die sooner.

The Application: The 5 AM Interval Dilemma 🚲

This brings us to the classic problem for the "Deliberate Cyclist" who balances a career and family.

You have a job. You have kids. The only time you can ride is 5:00 AM. To get 7+ hours of sleep, you need to be asleep by 9:30 PM. If you go to bed at 11:30 PM and wake up at 5:00 AM to smash a threshold workout, you are getting 5.5 hours of sleep.

Based on this data, that workout is likely doing you more harm than good.

We convince ourselves that the aerobic benefit of the ride outweighs the systemic stress of the sleep deprivation. This study suggests otherwise. By cutting sleep to train, you are prioritizing a secondary metric (fitness) over a primary metric (mortality risk and systemic health).

The Protocol for the Deliberate Cyclist:

1. The 7-Hour Hard Floor: Treat 7 hours of sleep with the same rigidity you treat your FTP. If you can't get the hours, you don't have the physiological budget to absorb the training stress.
2. Shift the Volume: If you can't sleep enough during the week, shift your volume to the weekends. High-intensity, low-volume work during the week requires less time, allowing for more sleep.
3. Data Hygiene: If you track your TSS (Training Stress Score) but not your sleep duration, your data is incomplete. You are tracking the expense but ignoring the income.

The Verdict

Stoicism teaches us to distinguish between what we can control and what we cannot. We cannot control our genetics. We cannot control the weather on race day.

We can control when we turn off the lights.

The culture of endurance sports often fetishizes suffering—the "grind." But there is nothing tough about biological mismanagement. It is simply inefficient. This study confirms that sleep insufficiency is a mortality risk on par with some of the most dangerous lifestyle factors we know.

Ride hard. But if you want to ride for a long time—literally and metaphorically—sleep harder.

TL;DR

1. New Data is Clear: A massive 2019-2025 study shows insufficient sleep (<7 hours) is linked to shorter life expectancy, with a stronger correlation than physical inactivity.
2. Mechanism: Sleep deprivation acts similarly to smoking or obesity in its impact on mortality risk; it is a systemic biological stressor, not just a feeling of fatigue.
3. The Trade-off: If you are cutting sleep to fit in training, you are likely negating the health benefits of the exercise. Prioritize 7 hours of sleep as your primary training metric.