Morning Running: Physiological, Performance, and Logistical Disadvantages

What are the disadvantages of running in the morning?

While morning runs offer distinct advantages like consistency and a fresh start, they can also present specific physiological, performance, and logistical challenges that may not suit every runner or training goal.

Physiological Stiffness and Reduced Readiness

Upon waking, the human body is not immediately primed for high-intensity physical activity. Several physiological factors contribute to this initial state of reduced readiness:

• Lower Core Body Temperature: During sleep, core body temperature naturally dips. A lower temperature can decrease the elasticity of muscles, tendons, and ligaments, making them less pliable. It also reduces the efficiency of enzymatic reactions crucial for energy production, potentially affecting power output and endurance.
• Joint Stiffness: Synovial fluid, which lubricates our joints, tends to be thicker and less abundant after a prolonged period of inactivity (sleep). This can lead to a sensation of stiffness and reduced range of motion, particularly in weight-bearing joints like the ankles, knees, and hips.
• Circadian Rhythm Effects: Our internal biological clock (circadian rhythm) influences various physiological processes, including hormone levels, metabolism, and nerve conduction velocity. For many, peak physical performance markers, such as strength, power, and coordination, tend to be higher in the late afternoon or early evening, rather than first thing in the morning.

Elevated Injury Risk

Directly stemming from the physiological stiffness and reduced readiness, running without an adequate warm-up in the morning can increase the risk of injury:

• Inadequate Warm-Up: Rushing into a run without a proper dynamic warm-up to elevate body temperature, increase blood flow to muscles, and improve joint mobility leaves tissues vulnerable. Cold, stiff muscles and connective tissues are more prone to micro-tears, strains, and sprains.
• Compromised Proprioception: Proprioception, our body's sense of position and movement, can be slightly dulled upon waking. This can lead to less coordinated movements and a greater likelihood of missteps, especially on uneven terrain.

Suboptimal Performance Potential

For runners focused on performance, early morning runs might not always yield the best results:

• Reduced Power and Speed: Due to lower body temperature and muscle stiffness, force production and the rate of force development (power) may be diminished compared to later in the day. This can make high-intensity interval training or speed work less effective.
• Perceived Effort: The same pace or distance might feel more challenging in the morning due to the body's lower state of readiness, potentially impacting mental fortitude and overall training quality.
• Glycogen Stores: If fasted overnight, liver glycogen stores might be partially depleted. While muscle glycogen stores are generally preserved, a lack of readily available blood glucose can affect sustained performance, especially on longer runs, unless a pre-run snack is consumed.

Environmental and Safety Concerns

Depending on location and season, morning runs can present specific external challenges:

• Darkness and Low Light: Early mornings, particularly outside of summer months, often mean running in the dark. This significantly increases safety risks due to reduced visibility for both the runner (tripping hazards, uneven surfaces) and others (vehicles, cyclists).
• Colder Temperatures: Morning temperatures are typically the lowest of the day. This requires more careful layering of clothing to prevent hypothermia, and can make the initial minutes of a run less comfortable.
• Increased Humidity/Dew: Early mornings can be prone to higher humidity or dew, making surfaces slippery and potentially increasing the risk of falls.

Sleep Disruption and Circadian Rhythm Impact

For individuals who struggle with sleep or have specific chronotypes, early morning runs can be detrimental:

• Reduced Sleep Duration: Consistently waking up earlier to run can lead to chronic sleep deprivation if the bedtime isn't adjusted accordingly. Adequate sleep is crucial for muscle repair, hormone regulation, and overall recovery.
• Circadian Rhythm Mismatch: Not everyone is a "morning person." For "night owls," forcing an early morning run can conflict with their natural circadian rhythm, leading to feelings of fatigue, reduced motivation, and potentially affecting mood and cognitive function throughout the day.
• Compromised Recovery: If sleep is cut short, the body misses out on vital stages of sleep where growth hormone is released and cellular repair processes are most active, potentially hindering recovery from previous training.

Logistical Hurdles and Motivation

Practical considerations and psychological factors can also pose disadvantages:

• Time Constraints: Fitting a run, warm-up, cool-down, and post-run routine into a tight morning schedule before work or other commitments can be stressful and lead to rushing.
• Difficulty Getting Started: For many, the mental hurdle of getting out of a warm bed and into running gear, especially on cold or dark mornings, can be a significant barrier to consistency.
• Pre-Run Nutrition: Deciding whether to run fasted or consume a quick snack requires planning and can be a source of gastrointestinal discomfort for some.

Gastrointestinal Considerations

Running on a "sleeping" digestive system or immediately after a quick meal can lead to discomfort:

• Digestive Upset: The digestive system may not be fully "awake" or ready to process food efficiently first thing in the morning. Consuming a meal too close to a run can lead to cramping, side stitches, or the urge to use the bathroom.
• Fasted Running Discomfort: While some prefer fasted morning runs, it can lead to low blood sugar symptoms (dizziness, fatigue) for others, particularly on longer or more intense efforts.

In conclusion, while morning running is a popular choice for its consistency and mental benefits, it's crucial to acknowledge its potential drawbacks. Understanding these disadvantages allows runners to make informed decisions, implement appropriate warm-up and recovery strategies, and select the optimal training time that aligns with their individual physiology, lifestyle, and performance goals.