Do I need to carb-load for a half-marathon?
Not in the multi-day sense like a marathon. One big carb-rich lunch the day before is enough for most fit athletes. The 21 km distance doesn't deplete glycogen the way 42.195 km does.
Half marathon · 10-day taper
Half-marathon race week — day-by-day taper and race morning
Half-marathon taper is shorter and lighter than marathon. Glycogen depletion isn't the same risk — most fit half-marathoners can race off normal stored glycogen with a single big carb-rich lunch the day before. The taper is more about freshness and pacing rehearsal than depletion management.
This is the day-by-day plan we run inside SportPlan for half-marathon athletes — adjusted by the engine based on HRV, Body Battery, and load trend, but here it is in its template form.
Day-by-day plan (the final 8 days)
T-7
Sunday before race-Sunday
Last quality long run — 14–18 km easy, 5 km at race pace at the end
Your last meaningful long-run-with-quality. Keep total volume conservative: 14–18 km. Insert a 5 km race-pace section in the final third. This is the last day for a real workout.
T-6
Monday
30–40 min easy or rest
Easy 30–40 min run or full rest. Sleep priority. Hydrate normally — no aggressive electrolyte loading needed yet.
T-5
Tuesday
40–50 min easy + 4×100m strides
Light easy run with 4×100m strides at goal half-marathon pace. Strides keep neuromuscular speed alive without adding fatigue. Normal nutrition.
T-4
Wednesday
Optional workout — 6–8 × 400m at 5K pace OR easy 40 min
Optional last quality session. Short 5K-pace intervals (400m repeats with 200m jog) keep top-end fitness without adding load. If you feel anything off, default to easy 40 min instead.
T-3
Thursday
Rest or 20–30 min very easy
Real rest day. If you must move, walk or jog 20–30 min very easy. Sleep, hydrate, eat normally. Start paying attention to bib pickup logistics and race-morning timing.
T-2
Friday
30 min easy + 3×100m strides at race pace
Easy 30 min with 3 strides at goal race pace. Final pace-feel rehearsal. Lay out your race kit and check forecast. Avoid new foods.
T-1
Saturday — race eve
Big carb-rich lunch + 10 min shakeout + 2 strides
Optional 10 min shakeout with 2×30s pickups at race pace. The main event today is your lunch: large, carb-rich, normal foods (rice, pasta, bread). One meal, not a multi-day load. Light dinner before 7 PM. Lay out gear, charge watch, prep gels.
Race
Race day
2–2.5 hour fueling window, then go
Wake 2–2.5 h before gun. Breakfast: bagel + banana + small coffee. 120–180 g carbs total. 45 min before: 25 g carbs (gel or sports drink). Dynamic warm-up + 4×100m strides 10 min before. Start the first 3 km at goal pace +5 sec/km. Settle into pace by km 5. One gel at km 8 if racing over 1:45.
Carb intake — simpler than marathon
Half-marathon doesn't need a multi-day carb load. Most athletes have enough stored glycogen for 21 km if they eat normally and have a carb-rich lunch the day before.
Day-before lunch target: ~3 g carbs per kg bodyweight at a single meal. For a 70 kg athlete that's ~210 g — a big plate of pasta, rice, or potatoes.
Day-before dinner: lighter than lunch. Smaller portion, low-fat, low-fibre. The goal is to wake up not bloated.
Race-morning fueling timing
2–2.5 hours before gun: 1.5 g carbs per kg bodyweight (bagel, oatmeal, toast). 200 ml water. Coffee if you're caffeinated.
45 minutes before gun: 25 g carbs as gel or sports drink. Sip water.
During race: one gel mid-race if you're racing over 1:45. Faster runners often don't need any in-race fuel — water at every aid station is enough.
Pacing — the half-marathon's specific trap
The half is easy to start too fast. The first 5 km feels light because glycogen is full and adrenaline is high. Plenty of athletes blow up at km 16 because they ran the first 5 km 10–15 sec/km too fast.
Target an even split or a slight negative split. The first 3 km should feel comfortable, the next 10 km should feel sustainably hard, and the last 5 km should feel like a hard 5K.
Half-marathon race-week FAQ
Can I do a tune-up race during half-marathon taper?
Yes — a 5K tune-up 10–14 days out is a classic sharpening tool. But not during the final 8 days. A race within the last week creates more fatigue than benefit.
How fast should my strides be during taper week?
Strides are 100m at goal half-marathon pace or slightly faster (5K pace works too). Not sprints — controlled, smooth, with 30 seconds easy walking between each. The goal is neuromuscular activation, not stimulus.
Should I take caffeine on race morning if I don't normally?
No. Race week is the wrong time to introduce caffeine if you don't use it. The performance edge from caffeine (1–3%) is real, but only if you've trained with it. Cold-starting on race morning risks GI distress.
What if my last long run before race week was bad?
A bad last long run usually reflects accumulated fatigue from the build, not lost fitness. Tapering will resolve it. Don't try to fix it by adding a redemption workout — that's how athletes arrive at race day cooked.
Related guides and tools
Half-marathon race-week, auto-adjusted
SportPlan reads your HRV trend through taper week — if you're under-recovered going into Friday, the plan auto-adjusts. See your first week before you pay. €9.99/month, cancel anytime.
Methodology
Methodology designed by Ramon Curto, MSc Exercise Physiology
Ramon Curto designed SportPlan's endurance-training methodology from exercise-physiology principles. SportPlan applies it autonomously to the information you enter and the data you choose to connect; it is not ongoing one-to-one coaching or medical care.
Last revised July 2026
- MSc Exercise Physiology
- Endurance-training methodology
- Connected training-data analysis
- Block periodization · Polarized training