# Why your run always starts so hard

> The first 10 to 15 minutes feel brutal because your muscles and oxygen system are out of sync. Here's what's happening and how to ease it.
- Title: Why your run always starts so hard · Daily Maverick | Shortify
- Summary: The first 10 to 15 minutes feel brutal because your muscles and oxygen system are out of sync. Here's what's happening and how to ease it. The difficult…
- Keywords: running, exercise physiology, oxygen uptake, warm-up, endurance training, fitness, news, politics, run, always, starts, hard
- Source: Daily Maverick — https://dailymaverick.co.za/article/2026-10-13-why-the-start-of-your-run-feels-so-difficult
- Author: Richard T. Longoria
- Published: 2026-10-13T15:00:00+00:00
- Read time: 2 min
- Topics: running, exercise physiology, oxygen uptake, warm-up, endurance training, fitness, news, politics
## The first 10 to 15 minutes
Many runners describe the first ten to fifteen minutes of a run as the hardest of all. Breathing feels laboured, legs feel heavy and a manageable pace suddenly feels surprisingly difficult.
## It's not about fitness
This sensation affects almost everyone, from someone attempting their first five kilometre run to elite endurance athletes. It's caused by a normal feature of human physiology, not lack of fitness.
## Muscles versus oxygen system
When you begin running, an argument starts between your muscles and your cardiorespiratory system. Your working muscles demand rapid energy almost instantly, but the system producing that energy from oxygen cannot respond quite as quickly.
## Three phases of adjustment
Oxygen uptake kinetics describes how rapidly the body increases oxygen consumption when exercise begins.This transition unfolds in three phases.First, the body increases blood flow and oxygen.Second, muscles activate aerobic energy production.
## Bridging the energy gap
Before reaching steady state, muscles still need energy.The body temporarily relies on energy stored within the muscle.
## When it suddenly clicks
Around ten to fifteen minutes into a run, many runners report that something suddenly changes.The pace feels smoother, breathing becomes more controlled and the run settles into a rhythm.

> Around 10 to 15 minutes into a run, many runners report that something suddenly changes.
## Athletes adapt faster
Trained endurance athletes can increase oxygen uptake around forty to sixty percent more rapidly than amateur athletes. This is due to years of endurance training producing adaptations within their cells, muscles and cardiovascular systems.
## Three ways to ease the struggle
A gradual warm-up is the most effective strategy.Easy jogging, brisk walking or progressive pace increases raise muscle temperature and activate the aerobic system before the main run.Starting slightly slower than intended pace also helps.
## Key takeaway

The difficult start to a run is caused by a lag in oxygen delivery as the body adjusts to exercise, affecting almost all runners regardless of fitness level.