Running: Why the Start is Hard, Physiological Reasons, and Strategies to Ease It

Why is running hard at the start?

The initial difficulty experienced when starting a run is a common phenomenon rooted in the body's complex physiological and biomechanical processes as it transitions from a state of rest to high-demand aerobic activity, coupled with psychological adjustments.

The Body's Transition: A Physiological Lag

When you begin running, your body isn't immediately ready to meet the high energy demands of sustained activity. It undergoes a series of critical physiological adjustments that take time to optimize, creating the sensation of initial struggle.

• Oxygen Deficit and Anaerobic Reliance: At the onset of exercise, your body cannot deliver oxygen to your working muscles fast enough to meet the immediate energy demand. This initial period is known as the oxygen deficit. To compensate, your muscles primarily rely on anaerobic energy systems (ATP-PCr system and anaerobic glycolysis). This rapid, oxygen-independent energy production leads to the accumulation of metabolic byproducts, such as lactate, which contributes to the burning sensation and fatigue experienced early in a run. As your cardiovascular and respiratory systems catch up, you transition to more efficient aerobic metabolism, often described as hitting your "second wind."
• Cardiovascular System Lag: Your heart rate, stroke volume (the amount of blood pumped per beat), and the dilation of blood vessels (vasodilation) all need time to increase and deliver sufficient oxygenated blood to your muscles. At rest, blood flow is distributed throughout the body; during exercise, it needs to be preferentially shunted to the working muscles. This redirection and increased flow take several minutes to become fully efficient.
• Respiratory System Adjustment: Your breathing rate and depth must increase to take in more oxygen and expel carbon dioxide. This process is not instantaneous and requires coordination between your nervous system and respiratory muscles.
• Enzyme Activation and Metabolic Pathways: The various enzymes and metabolic pathways responsible for aerobic energy production (e.g., those involved in the Krebs cycle and oxidative phosphorylation) are not fully active at rest. They require time to "switch on" and reach optimal functioning.

Biomechanical and Neuromuscular Considerations

Beyond the internal physiological shifts, your musculoskeletal and nervous systems also need to prepare for the repetitive, high-impact nature of running.

• Joint Stiffness and Synovial Fluid: After periods of rest, the synovial fluid within your joints (e.g., knees, hips, ankles) is thicker and less viscous. As you begin to move, the fluid warms up and becomes thinner, improving joint lubrication and reducing stiffness. This is why initial movements can feel "creaky" or restricted.
• Muscle Activation and Coordination: Your nervous system needs to efficiently recruit the appropriate muscle fibers (especially slow-twitch fibers for endurance) and establish optimal motor unit firing patterns for running gait. This involves coordinating multiple muscle groups for propulsion, shock absorption, and stabilization, which requires a brief period of "rehearsal" or warm-up.
• Connective Tissue Elasticity: Tendons and ligaments, which are crucial for transmitting force and providing elasticity, also benefit from a gradual warm-up to become more pliable and less prone to injury.

Psychological Factors

While physiology plays a dominant role, the mind's perception and readiness also contribute to the initial challenge.

• Perceived Exertion: The physiological strain described above (oxygen deficit, lactate accumulation) directly translates into a higher perceived exertion during the initial minutes of a run. Even if the pace is slow, the body's internal struggle makes it feel harder.
• Mental Warm-up: Just as your body needs to adapt, your mind needs to shift focus and commit to the activity. Overcoming inertia and pushing past the initial discomfort requires mental fortitude and can be a significant hurdle for many.

Strategies to Ease the Start

Understanding why running feels hard at the start empowers you to implement strategies to make those initial minutes more manageable and enjoyable.

• Prioritize a Dynamic Warm-Up: Instead of static stretching, perform 5-10 minutes of light dynamic movements before you start running. This includes:
  • Leg swings (forward/backward and side-to-side)
  • Arm circles
  • Walking lunges
  • High knees and butt kicks (walking)
  • Light jogging or brisk walking This gradually increases heart rate, blood flow, and prepares muscles and joints.
• Start Slowly and Gradually Progress: Begin your run with a very easy, conversational pace—even slower than you think you need to. For the first 5-10 minutes, focus on simply moving. Once your body feels more comfortable, you can gradually increase your pace. Consider a run-walk strategy for longer runs or if you're new to running.
• Consistent Training: Regular running sessions lead to physiological adaptations that reduce the magnitude of the oxygen deficit and improve the efficiency of your cardiovascular and muscular systems. The more consistently you run, the less pronounced the initial struggle becomes.
• Proper Pacing: Avoid the temptation to start too fast, even if you feel energetic. An overly aggressive start will exacerbate the oxygen deficit and lead to premature fatigue.
• Hydration and Nutrition: Ensure you are adequately hydrated and have consumed appropriate pre-run fuel (if needed) well before your run. Dehydration and low energy stores can make any run feel harder, especially at the start.

When to Consult a Professional

While initial discomfort is normal, persistent or severe pain, unusual shortness of breath, chest pain, or dizziness during the start of a run should be evaluated by a healthcare professional. An exercise physiologist or a certified running coach can also provide personalized advice on warm-up routines, training strategies, and injury prevention.