20/08/2026
Battery....🔋🏃♀️📈📉
I speak to many ultra runners pre their long solo or multi day races focussing on managing energy through the event.
Most think it’s about replacing fuelling and energy, but we simply cannot do that how we want or think we can, so I use an analogy about the phone battery to help shape their thinking.
The conversation shouldn’t be about “How do I keep my energy levels up?” but more around “How do I control the rate at which I spend a finite resource?”
You’re not trying to keep or fill the battery back upto 100%. You’re trying to make sure there’s enough battery left for what the day or days still demand.
At the start of an ultra, imagine your body is a phone leaving home with a full charge.
From the moment you start, the battery is going down. That is normal. Eating, drinking and pacing intelligently don't recharge you back to 100%; they help manage the rate of depletion and preserve your ability to keep producing useful work.
And importantly, distance travelled doesn't necessarily predict battery used.
You might reach 50 km of a 100 km race with 65% remaining. Another runner might have 35%. Same distance. Very different energy cost.
Your screen brightness is intensity. Turn it up too high early because you feel fantastic, and you're paying for it all day.
Your GPS/navigation is terrain. Steep climbs, technical descents, mud, altitude and difficult footing can quietly increase the cost of every kilometre.
Your data roaming is the environment. Heat, cold, humidity and altitude can create additional physiological costs in the background.
Your apps running in the background are all the things consuming resources without necessarily making you faster: poor movement economy, unnecessary surges, carrying excess kit, inadequate conditioning, stress, poor sleep, GI problems, even repeatedly chasing other runners.
And fuel and hydration are simply power management, not a magical charger. They support continued work and can slow the deterioration in performance, but they don't erase accumulated fatigue.
Sometimes your phone goes from 70% to 50% much faster than expected. That's an ultra.
Rather than immediately thinking “I'm having a bad day” ask: What's draining the battery?
Maybe you've been running the climbs you planned to walk. Maybe the temperature has risen. Maybe you've stopped eating because your stomach feels poor. Maybe you've spent two hours unconsciously matching somebody else's pace. Maybe the technical terrain is costing considerably more than the distance suggests.
Then you have the ultra equivalent of low-power mode.
Walk the climb. Reduce pace. Cool yourself. Sort the fuelling problem. Stop racing the person ahead. Spend longer at the aid station if there's a problem worth fixing. Change the strategy before the battery warning becomes critical.
That isn't necessarily failure or weakness. It's resource management.
Multi-day ultras make the analogy even better.
For a single-stage ultra, the question is: How much battery do I need left for the final third?
For a multi-day event, it becomes: How much battery can I afford to use today without compromising tomorrow?
And unlike a phone, overnight recovery doesn't necessarily restore you to 100%.
You might start:
Day 1: 100% → 55%
Recover overnight → Day 2: 82%
Finish Day 2 → 43%
Recover → Day 3: 68% etc etc …..
That accumulated deficit changes the strategy. The athlete who repeatedly empties the battery trying to maximise each individual day may progressively reduce what they have available for subsequent stages.
The battery percentage isn't just about energy stores. It's a metaphor for your overall capacity to sustain the task: metabolic resources, muscular fatigue and damage, thermoregulation, hydration, GI tolerance, cognitive fatigue, motivation and other interacting constraints.
And different systems can become the limiting factor at different times.
You could effectively have 60% battery remaining but an app has crashed — your legs are capable of continuing, but nausea means you can't fuel properly. Or metabolically you're okay, but repeated descending has created enough local muscular fatigue that running is becoming disproportionately expensive.
That's why good ultra management isn't simply “eat X grams of carbohydrate per hour and hold X pace.”
It's repeatedly asking: How quickly am I draining? What's causing that drain? What's coming next? And what can I change now to make sure the battery lasts until I actually need it?
The best ultra runners aren't necessarily the ones with the biggest battery. They're often the ones who understand when to spend it, when to conserve it, and what is draining it.
Great analogy that can be applied to many aspects of your life...not just running🔋🏃♀️📉📈
Thanks The Endurance Physio for the wisdom 👌🫶👏
