Marathon prep is changing
Runners prepping for big spring marathons are focusing less on mileage and more on precise nutrition, hydration and heat adaptation. The Independent reports athletes like Sara Keenan are hiring nutritionists to dial in race‑day fueling, while coaches are using heat training — saunas and hot baths — to boost spring performance; race science guides are also stressing sweat testing and hydration strategies to avoid ‘hitting the wall’ (the-independent.com) (independent.co.uk) (independent.co.uk). The scale is striking too — over 1,100,000 people entered the 2026 London Marathon ballot, so competition for spots and race logistics matter more than ever (therunningchannel.com).
A spring marathon used to mean one obvious question: how many miles are you running each week. This year, runners chasing London and Boston are spending just as much time on gels, sodium and hot baths as they are on long runs. (independent.co.uk) Sara Keenan wrote that she hired a nutritionist before the 2026 London Marathon and changed not just race-day eating but her daily routine, including when she ate carbohydrates and how she managed energy around training. Her account is a sign of marathon prep moving from “run more” to “fuel on purpose.” (independent.co.uk) The race-day problem is simple: a marathon is 26.2 miles, and many runners run out of usable energy before they run out of road. That crash is the “wall,” and The Independent’s Jack Rathborn says runners are now using sweat tests and planned fueling to avoid it. (independent.co.uk) A sweat test is basically a lab version of tasting how salty your workout shirt gets. It measures how much sodium you lose, so a runner who sweats heavily does not copy the same drink plan as someone who barely salts up at all. (independent.co.uk) Heat training is the other shift, and it sounds strange until you picture it as rehearsal for a hard day. Coaches told The Independent that runners are using saunas, hot-water immersion baths and extra layers to force the body to practice cooling itself before race morning arrives. (independent.co.uk) That idea is not just locker-room folklore. Researchers writing in The Conversation reported that five weeks of regular hot baths increased red blood cell volume in trained runners, which can help move more oxygen during long efforts without adding extra mileage. (theconversation.com) The timing matters because spring marathons are unpredictable, and Boston is famous for weather swings while London can still surprise runners with warm conditions. A runner who trained through winter in cool air can arrive fit but still unravel if heat and hydration were never part of the plan. (independent.co.uk) The scale of these races is pushing the change too. The 2026 London Marathon drew a record 1,133,813 ballot entries, according to race guides, which means more first-timers and more runners treating race week like a logistics exercise instead of a casual Sunday jog. (the5krunner.com) London’s own event guidance now reads like an operations manual: runners must collect bibs at the Running Show at ExCeL London before race day, and the official hydration guide tells runners to match fluid plans to distance and conditions. The modern marathon is still about endurance, but the winning habit is increasingly precision. (therunningchannel.com) (londonmarathonevents.co.uk) The old badge of honor was the monster training week. The new one is getting to mile 20 with enough carbohydrate left, enough sodium left and a body that has already spent a few weeks learning what heat feels like. (independent.co.uk 1) (independent.co.uk 2) (independent.co.uk 3)
