Tag: stamina

Posted on

Sleep as the Hidden Stamina Booster

Day 18 of 100 Days Muscle Resistance Workout Challenge

Topic: Cardio Connection: Notice how your sleep affects your stamina during cardio

Learning Material 

Sleep doesn’t just reset your mind; it’s also one of the strongest performance enhancers for cardio. When you run, cycle, or row, your body needs oxygen delivery, a stable heart rate, and muscular endurance — all of which depend on the quality of last night’s sleep.

Key Insights:

  1. Oxygen Efficiency: Deep sleep (especially slow-wave sleep) helps restore the cardiovascular and respiratory systems. Poor sleep reduces oxygen uptake, meaning you’ll feel winded sooner.
  2. Heart Rate and Recovery: Good sleep lowers resting heart rate and improves heart rate variability (HRV). These are markers of endurance. A poor night’s sleep can cause your heart rate to spike earlier, making even moderate cardio feel harder.
  3. Perceived Effort: Research shows sleep-deprived athletes rate workouts as more difficult, even when performance metrics are the same1. In other words, your brain tells you “this is exhausting” much earlier when you’re tired.

Real-World Example:


 Think of cardio like filling a water balloon. With enough sleep, the balloon stretches easily and fills smoothly. With little sleep, the balloon feels stiff — you can still fill it, but it resists and feels harder. That resistance is how your body interprets cardio effort after poor rest.

My Reflection

I’ve been tracking my sleep for years, and I clearly see how it shapes my performance the following day. When I get fewer than seven hours, my mental focus drops sharply and my energy is noticeably lower.

Sleep quality is just as important as duration. External disturbances, like thunder or nighttime noise, can wake me and cut into my rest. On those nights, my cardio performance the next day is always worse. I’ve noticed that the depth and balance of my sleep cycles — especially how much deep sleep and REM sleep I get — make a real difference.

I’ve made a change to my diet. I have been eating much less protein than I need. My husband has kidney disease, and he is restricted in protein intake. To simplify meal preparation, I was eating the same amount of protein. No matter how much exercise I do, I feel like I’ve been losing my muscle mass.

I need to get enough protein, so I started taking an adequate amount. Since increasing my protein intake to support muscle repair, I’ve been sleeping more soundly. That was a new discovery for me. Typically, I fall into deep sleep quickly, followed by a shorter REM cycle, and then a longer, restorative REM period later in the night.

I also avoid being jolted awake during deep or REM sleep. To keep my rhythm natural, I rarely set an alarm unless absolutely necessary. Most mornings I wake up on my own, usually between 5:00 and 5:20 a.m., feeling refreshed.

Biometric data

Change in Weight from Day 1: -2.0 lb.

Skeletal Muscle: 39.10%

Muscle Mass: 94.8 lb.

Adjustment Ideas (Strategic adjustment):

  1. Bedtime Consistency: Set a fixed “lights-out” window (even within 20 minutes) to stabilize recovery.
  2. Pre-Cardio Fuel: If sleep was short, try a small carb boost before cardio (like half a banana) to reduce the sluggish feeling.
  3. Mindset Cue: On low-sleep days, accept a lighter cardio pace. Focus on moving consistently rather than pushing intensity.
Day 17

Note

  1. Yan Kong et al., “(PDF) Effects of Sleep Deprivation on Sports Performance and Perceived Exertion in Athletes and Non-Athletes: A Systematic Review and Meta-Analysis,” ResearchGate, ahead of print, August 10, 2025, https://doi.org/10.3389/fphys.2025.1544286. ↩︎
Posted on

Back To 10K Runs In the Heat

Written July 27, 2024

Hello Dear Readers,

Today is a Saturday, and like most Saturdays, I aim to complete a 10k run. However, I haven’t been able to stick to this goal consistently due to the heat, which makes running quite uncomfortable. To address this, I’ve adjusted my schedule and run early in the morning when the temperature is more relaxed. This change has allowed me to start doing 10k runs again recently.

My nephrologist recommended using a running app to track my progress, so I tried it. I completed my weekly 10k run this morning, but around the 8-kilometer mark, I lost focus and couldn’t remember how far I had run. Thankfully, I’m very familiar with my route, so I kept going until the app announced my distance. Hearing the app’s voice confirming that I had reached my goal was a relief.

I use a free app from Asics that provides updates at set intervals. I’ve configured it to announce my progress every minute, which helps me stay motivated and on track. My wife, however, finds frequent updates distracting and has her app set to announce every five minutes. It’s interesting how we each find different ways to stay focused during our runs.

I’m pleased to have completed another 10k run, although I felt exhausted afterward. I suspect that my body is adjusting after not running this distance regularly for a while. In 2023, I ran 10k thrice a week, so not keeping up that frequency has likely impacted my stamina. While I can still complete the distance, my pace has plateaued, and pushing myself to run faster during 10k runs has been challenging.

I’ve focused more on 5k runs weekly to improve my speed. Running shorter distances allows me to concentrate on increasing my pace without the fatigue of longer runs. This adjustment is a more manageable approach for now. In the future, I may need to revise my running schedule further, but for now, I’ll continue with this plan.

Getting back into the routine of regular 10k runs has been a rewarding experience, even if it is only once a week. I’m eager to see how my performance improves with consistent training. The journey back to my previous fitness level is challenging. Still, I’m confident that I’ll continue to make progress with perseverance and the right strategy.