Aaerix

Sub 3:45 Marathon Pace Chart & Training Guide

Complete pace chart for running a sub 3:45 Marathon. Target pace: 5:20/km (8:35/mi). Includes km splits, training plan, and race-day strategy for recreational runners.

Target Time

3:45:00

Pace (min/km)

5:20

Pace (min/mi)

8:35

Speed

11.3 km/h

Pace Chart
Finish TimePace (min/km)Pace (min/mi)Speed (km/h)
3:44:005:198:3311.3
3:45:005:208:3511.3
3:46:005:218:3711.2

Training for a Sub 3:45 Marathon

Running a Marathon in under 3:45 requires a pace of 5:20 per kilometer (8:35 per mile). This is a realistic goal for recreational runners who commit to a structured training plan over 8-16 weeks. Your weekly mileage should be in the 50-65 km range, with three quality sessions per week: one interval workout, one tempo run, and one long run. The key interval session is 3×3km @ 5:15/km with 90-second recovery jogs. Your tempo runs should be 35 min @ 5:25/km, building the lactate threshold endurance you need to hold race pace when fatigue sets in. Long runs should be 25-30% of your weekly volume, run at a comfortable pace 60-90 seconds slower than your target race pace. Consistency matters more than any single workout. Missing one session is fine, but missing a full week sets your aerobic base back by roughly two weeks. If you are coming off a break, add no more than 10% weekly mileage per week to avoid injury. As an intermediate runner, consistency is your biggest performance lever. Running 4-5 days per week with modest volume beats running 3 days with higher intensity. Your body needs the repeated aerobic stimulus to build capillary density and mitochondrial function. Do not skip easy days. Easy running at 65-75% of max heart rate builds your aerobic engine without the recovery cost of hard sessions. If you are injury-prone, replace one run per week with swimming or cycling. Cross-training maintains fitness while giving your joints a break. Foam rolling and dynamic stretching before runs reduces injury risk significantly. Sub-3:45 marathon at 5:20/km sits in the efficient zone where you run fast enough to benefit from carbohydrate loading but slow enough that hydration strategy matters more than fueling. Carb-load for 3 days before the race by eating 8-10g carbs per kg body weight daily. On race morning, eat your practiced pre-race meal 3 hours before start. During the race, drink to thirst at every aid station but do not force fluids. Hyponatremia from overdrinking is a real risk at this pace.