The carbohydrate strategy that keeps output steady from minute one to the final whistle.
The carbohydrate strategy that keeps output steady from minute one to the final whistle.
Ninety minutes sits in an awkward middle ground. Long enough that what you ate three hours ago starts to matter, short enough that most people assume they can wing it.
That assumption is where the energy crash lives.
The physiology is straightforward enough: your body stores roughly 90 to 120 minutes of glycogen at moderate-to-high intensity, but that ceiling drops fast when you factor in heat, a hard warm-up, or the kind of stop-start intensity that team sport and interval training demand. A 90-minute session isn't a gentle draw on your reserves, it's often a near-complete withdrawal, and what you bring to the session determines whether you finish strong or spend the last twenty minutes running on fumes.
Pre-session nutrition does more work than most athletes give it credit for. A meal containing carbohydrate eaten two to three hours before training sets your glycogen stores in a position to last. The mistake isn't usually eating too little, it's eating too late, or eating the wrong things. A large, high-fat meal ninety minutes before a session slows gastric emptying and leaves you feeling heavy rather than fuelled. Something lighter and carbohydrate-forward, rice, oats, bread, eaten with enough lead time gives your body a chance to actually use it.
If your schedule doesn't allow a proper pre-session meal, a small carbohydrate snack thirty to forty-five minutes out can bridge the gap. This isn't ideal, but it's better than training fasted and hoping intensity stays manageable.
For sessions sitting right at that 90-minute mark, intra-session fuelling is where most recreational athletes leave performance on the table. The common belief is that you only need to eat during exercise if you're going longer than an hour. That's a reasonable rule of thumb for steady-state cardio at moderate intensity, it doesn't hold for high-intensity intermittent work.
When you're repeatedly pushing into higher heart rate zones, carbohydrate oxidation accelerates. Consuming 30 to 60 grams of carbohydrate per hour during intense exercise is well-supported by research in exercise physiology, and the practical implication is simple: a gel, a chew, or a sports drink taken around the 45-minute mark can meaningfully extend the quality of your output in the second half of a session. Not because you've run out of fuel by then, but because you're preventing the deficit from accumulating before it becomes a problem.
Hydration compounds the carbohydrate picture in a way that often goes unacknowledged. Even modest dehydration, around two percent of body weight, measurably impairs both physical and cognitive performance. In team sport, where decision-making under fatigue matters as much as physical output, this is not a trivial concern. Arriving well-hydrated and maintaining fluid intake across the session isn't a separate consideration from fuelling, it determines how effectively the fuel you've taken in can actually be used.
The fatigue that people associate with the end of a 90-minute session isn't always a fuelling failure in the moment, sometimes it's a recovery failure from the session before. Arriving at training with partially depleted glycogen stores means you're already behind before you start. Consistent post-session carbohydrate intake, particularly in the window immediately after training, keeps your baseline higher across a training week.
This is where the cumulative picture matters. One well-fuelled session doesn't transform your fitness. But training week after week with adequate carbohydrate availability, before, during, and after, means you're actually completing the sessions you intended to complete, at the intensity you intended to train at. The adaptation follows the stimulus, and the stimulus requires fuel.
Ninety minutes is long enough to get this wrong. It's also short enough that getting it right is entirely manageable.