How Beetroot Juice and Carbohydrate Availability Improve Endurance Economy and Late-Session Power
Use nitrate-rich beetroot juice and smarter carbohydrate timing to improve running economy, sustain training volume, and hold power late in long sessions.
If you’ve ever watched power or pace fall apart in the last 20 minutes of a hard session, you already know the problem: your legs are not just tired, they’re less efficient. The fix is often not more grit. It’s better substrate availability. In practice, the strongest evidence-backed combo is beetroot juice before training plus enough carbohydrate to keep high-intensity output available when it matters most.
Why this combination works
Beetroot juice is a nitrate delivery system. Dietary nitrate is converted to nitrite and then to nitric oxide, a signaling molecule that improves blood flow regulation, mitochondrial efficiency, and muscle contractile function. That matters for endurance economy: if you can produce the same pace or wattage with slightly lower oxygen cost, you preserve more reserve for the back half of the session (Jones, 2014; Lansley et al., 2011).
Carbohydrate availability solves a different bottleneck. When muscle glycogen is low, you lose the ability to sustain high rates of carbohydrate oxidation, force production drops, and perceived exertion climbs faster. Pre-exercise carbohydrate can improve repeated high-intensity efforts and late-session output, especially when the session is long, hard, or done after previous training stress (Cermak and van Loon, 2013).
Put simply: beetroot juice can make you more economical, and carbohydrate can make sure that economy is usable under fatigue.
What beetroot juice actually improves
The best-supported effect of nitrate supplementation is improved exercise economy and performance in submaximal to severe-intensity work. The classic finding is a reduction in oxygen cost at a given workload, often on the order of a few percent, which is small on paper and meaningful in a race or high-volume training block (Bailey et al., 2009; Lansley et al., 2011).
That matters most in these cases:
- Steady-state runs or rides lasting 30 to 90 minutes
- Tempo or threshold sessions where economy determines how long you can hold pace
- Repeated intervals with incomplete recovery
- Athletes who are not already heavily nitrate-adapted from long-term supplementation
Not every study shows a large effect, and response varies. But when it works, the practical outcome is simple: the same pace feels slightly less expensive, and late-session power is better preserved.
How carbohydrate availability changes the equation
Carbohydrate is the fuel that lets you keep power high when glycolytic demand rises. For endurance athletes, the biggest mistake is underfueling the session before and during the work. If muscle glycogen is pushed too low, you can still move, but you won’t hold quality across the full workout.
The data are clear that carbohydrate ingestion before and during exercise improves endurance performance, especially when exercise exceeds about 60-90 minutes or includes repeated high-intensity efforts (Jeukendrup, 2014). For serious trainees, this is not just about race day. It is about preserving training quality so you can accumulate more effective volume across the week.
A well-fueled athlete can complete more intervals at target power, sustain pace longer, and recover better between sessions. That is the real adaptation lever.
Why the combo can beat either strategy alone
Beetroot juice and carbohydrate act through different pathways, so they can complement each other. Nitrate may improve the efficiency of oxygen use and muscle performance, while carbohydrate ensures you have enough substrate to express that improved efficiency at higher intensities.
In plain English: nitrate may help you spend less to go the same speed, but carbohydrate makes sure the tank is actually full enough to use that advantage.
This is especially useful for:
- Morning training after an overnight fast
- Two-a-day sessions
- Long runs with quality pickups
- Mixed sessions with intervals after steady work
- Hybrid athletes who need endurance output without sacrificing strength work later in the day
There’s also a timing point here. If you take beetroot juice and train under-fueled, you may gain some economy, but you still cap the session with a depleted fuel tank. If you take it alongside a carbohydrate-adequate pre-session meal, you reduce the chance that substrate shortage becomes the limiting factor.
Practical dosing for beetroot juice
The research typically uses nitrate doses around 5 to 9 mmol, taken about 2 to 3 hours pre-exercise (Jones, 2014). That is the most useful starting point.
Start here
- Beetroot juice shot or concentrate: enough to provide 6 to 8 mmol nitrate
- Timing: 2 to 3 hours before training
- Frequency: use before key endurance sessions, time trials, races, or high-quality interval days
If you’re sensitive to GI upset, start with a lower dose and test it on a non-key session. Do not assume all beet products are equal. You want a standardized nitrate dose, not a random “superfood” serving.
Important execution details
- Avoid antibacterial mouthwash around dosing, because oral bacteria help convert nitrate to nitrite, and mouthwash can blunt that process (Govoni et al., 2008)
- Test the product in training, not on race day
- Expect red urine or stool sometimes; it is common and harmless
Practical carbohydrate targets before training
The right amount depends on session duration and how much quality you need to preserve.
For sessions under 60 minutes
- 20 to 30 g carbohydrate 30 to 60 minutes pre-session is often enough if you are otherwise well fueled
- If the session is very intense, use 30 to 60 g in the 1 to 3 hours before training
For sessions lasting 60 to 120 minutes
- 1 to 4 g/kg carbohydrate in the 1 to 4 hours pre-exercise, depending on time available and GI tolerance (Thomas, Erdman, and Burke, 2016)
- Example: a 70 kg athlete might use 70 to 140 g carbohydrate 2 to 3 hours pre-session if the workout is demanding
For long sessions or doubles
- Prioritize a carb-containing meal 2 to 4 hours pre-workout
- Add a top-up snack 30 to 60 minutes before if needed
- During exercise, target 30 to 60 g/hour for sessions over 90 minutes, and up to 90 g/hour for very long or race-specific work if using multiple transportable carbohydrates (Jeukendrup, 2014)
The goal is not to feel stuffed. The goal is to start with enough glycogen and circulating glucose to finish the workout at the intended quality.
What this means for endurance economy
Endurance economy is not just about oxygen consumption in a lab. It is about the energy cost of producing a given output. If beetroot juice reduces the oxygen cost of a fixed pace, you can potentially sustain that pace with less physiological strain. If carbohydrate is adequate, you can keep that pace from drifting downward as fatigue rises.
That is especially useful in sessions with a lot of “steady hard” work:
- 40 to 60 minutes at tempo
- Cruise intervals like 5 x 8 minutes
- Long intervals like 3 x 15 minutes
- Rolling rides with repeated surges
- Runs that finish with fast miles
In those sessions, economy and fuel availability are not separate issues. They compound.
What this means for training volume
More quality reps completed at the intended pace or power means more effective volume. Not junk volume. Effective volume.
A fueled athlete using beetroot juice may be able to:
- Keep interval pace more stable across later sets
- Reduce the pace drop-off in the last third of the session
- Recover better between reps because the session felt less metabolically costly
- Maintain better movement quality when sessions are stacked across the week
That matters in blocks where you need both endurance and power maintenance. The goal is not to turn every session into a race. The goal is to preserve the output needed to create the adaptation.
Late-session power output is where the payoff shows up
The clearest real-world benefit often appears when fatigue is already present. In hard interval sessions, racing, or long endurance efforts with a finishing kick, nitrate plus carbohydrate can help you keep power where others fade.
That is because late-session output depends on three things:
1. How much fuel is left
2. How much strain the current pace is creating
3. How much reserve you still have for surges
Beetroot juice can lower the cost of a given effort. Carbohydrate can keep the higher-end engine available. Together, they improve the odds that your last 10 minutes are productive instead of survival mode.
When this strategy is most worth using
Use it on days when output matters most:
- Threshold or VO2-focused run workouts
- Long ride with race-specific efforts
- Brick sessions
- Key group ride days
- Time trials or competition
- Hard training after a prior session or poor sleep, when quality is at risk
Do not waste the strategy on easy recovery days. Save it for sessions where better economy and preserved power can change the training effect.
How to apply this
Pre-session checklist for a key endurance workout
2 to 3 hours before
- Take beetroot juice providing 6 to 8 mmol nitrate
- Eat 1 to 3 g/kg carbohydrate depending on session length and GI tolerance
- Keep fat and fiber moderate if the session is hard
30 to 60 minutes before, if needed
- Add 20 to 30 g carbohydrate from a sports drink, banana, gel, or toast with jam
During the session
- Under 60 minutes: water is usually fine if you pre-fueled well
- 60 to 90 minutes: 30 to 45 g carbohydrate/hour
- Over 90 minutes: 45 to 90 g carbohydrate/hour depending on intensity and gut training
After the session
- If another hard session is coming within 24 hours, start recovery with 1.0 to 1.2 g/kg carbohydrate in the first hour and include 25 to 40 g protein
Example weekly implementation
Monday: recovery run or easy spin
- No beetroot juice needed
- Normal meals, modest carb intake
Tuesday: threshold session
- Beetroot juice 2.5 hours pre-workout
- 1.5 to 2 g/kg carbohydrate meal 2 to 3 hours pre-workout
- 30 g carbohydrate during if session exceeds 75 minutes
Thursday: VO2 or interval day
- Beetroot juice 2 to 3 hours pre-workout
- 2 to 3 g/kg carbohydrate pre-session
- 30 to 60 g/hour during if long enough to matter
Saturday: long endurance session with pickups
- Beetroot juice 2 to 3 hours pre-session
- 2 to 4 g/kg carbohydrate beforehand
- 45 to 75 g/hour during, especially if the session extends beyond 90 minutes
Race or time trial day
- Test the exact beetroot dose in advance
- Eat a carb-rich meal 3 to 4 hours before
- Add 20 to 30 g carbohydrate 30 minutes pre-start if tolerated
Bottom line for serious athletes
If your goal is better endurance economy, higher training volume, and stronger late-session power, do not treat beetroot juice and carbohydrate as separate hacks. Use them together, with intent. Take a standardized nitrate dose 2 to 3 hours pre-session, then make sure carbohydrate availability matches the workload. That combination supports better pacing, better output, and better training quality when it counts most.