Athletics Magazine

11 Reasons You Might Be Running Slower Than You Used To

By Brisdon @shutuprun

Yesterday was a 7 mile run with 5 miles at tempo pace. This was the first day in MONTHS I’ve been able to actually run in shorts since it was a balmy 44 degrees at 8:00 a.m. If I look tired, I am.


Pre-run coffee rocks my world. And my intestines.

I am noticing a trend. While I am hitting all of my speed work, tempo and long run mileages and paces, I am working harder to hit these paces than I have in the past. I thought it might be my imagination, but when I looked at my training notes from three years ago, I saw it was indeed, the sad truth. Not to say that paces are everything, but I am still wanting to see progress.

Surprisingly, there is not a wealth of information on this topic. But, here are some likely reasons that I, and you too, may be running slower than you have in the past.

1. Too little sleep. We all know lack of sleep can greatly affect performance as well as mood. When you run, you break down your body. You actually get microscopic tears in your muscles. Rest and recovery give your body the chance to heal these tears and to build even stronger muscles. If you are sleep deprived, this process happens less, or not at all. This can increase chance of injury and just make you feel like crap. Athletes who had too little sleep report reaching a point of exhaustion 11% more quickly than those who were well rested.  More info on how sleep deprivation affects training HERE.


Nothing wrong with a little drool

2. Not enough recovery from hard workouts. As stated above, running (especially doing speed work or other strenuous activities) causes fatigue and tearing in your muscles. If you don’t give yourself adequate recovery time, the recovery process doesn’t happen as it should. Take at least one rest day per week and incorporate recovery weeks where mileage is reduced about 1/4 to 1/3.

3. A recent boost in speed work and/or mileage. If your runs are causing soreness, fatigue and/or burn out, you may be doing too much too soon. An increase of no more than 10% per week regarding distance, frequency or intensity is recommended.

4. An iron deficiency (aka anemia). At first, the signs of anemia may be hard to detect, but as the body becomes more iron deprived, the symptoms become more noticeable. Signs that you have an iron deficiency include paleness, fatigue, shortness of breath, headache, cold hands/feet, fast heart rates, dizziness, irritability and possible soreness of the tongue. A quick blood test at your doctor can determine if you are anemic. Depending on the cause of the deficiency, different supplements and/or injections can be recommended. In general, women are at greater risk of anemia due to menstruation.

11 Reasons You Might Be Running Slower Than You Used To

5. Age. I hate to say it, but often times (not always!) runners slow down with age. Obviously this is the case or Boston age group qualifying times wouldn’t increase as entrants get older.  Perhaps a reason that as we get older we might get slower is that we become more injury prone, have increased body fat, have decreased VO2 max(10% per decade after the age of 30!), have a loss of range of motion and can lose muscle mass. Certainly there are ways to combat these issues such as strength training, yoga, diet, etc. For more info on how aging affects running speed, read this informative article from Runner’s World.

6. Stress. You’ve heard it a million times before. Stress takes a toll on the body and can result in a myriad of symptoms including headaches, elevated blood pressure, upset stomach, chest pain and difficulty sleeping. Naturally any or all of these conditions put an additional strain on the body and could contribute to a decline in running performance.

7. Diet. While running, and especially during training, special attention needs to be given to diet. The runner needs to ensure enough calories are being consumed to compensate for the amount burned (HERE is a good place to figure it out). In addition, it’s important to make sure you are getting the right amount of carbohydrates, protein and fats (40%/30%/30% is a good rule of thumb while marathon training). Lastly, hydration is key to flushing out your organs and carrying nutrients to your cells. Aim to drink 60 to 90 ounces of water per day (depending on how frequently you exercise).

8. Attitude. Are you starting your workouts with a lack of confidence or motivation? We have all heard the Henry Ford quote, “Whether you think you can or think you can’t – you’re right.” Prior to starting any workout, especially one where you will be pushing your limits, it’s crucial to get right in your head. Replace negative messages like “I am not strong enough to do this,” with uplifting thoughts such as, “Believe! You are capable, fierce, unstoppable.” Or, whatever works for you (more mantras HERE).

11 Reasons You Might Be Running Slower Than You Used To

9. An underlying medical condition. While this is probably a less common reason for slower running, it is always a possibility. If fatigue is persistent, see a doctor.

10. An injury. Although you may not have a full blown injury, if you are running with a nagging pain that won’t go away, you are likely altering your gait. This change in form just might be making you runs tougher than before. In addition, any pain while you are running will affect physical performance was well as mental well being. Take time off if you can’t shake an ache or pain. It could be the start of something that could become much, much worse.

11. Time of the year/weather/conditions. Heat, in particular, can affect running performance by elevating your heart rate and making you prone to dehydration. Other conditions such as wind, muddy trails, frozen sidewalks and driving rain or snow will also slow you down (duh!). Lastly, I find that winter temperatures (as well as summer heat) can wear on you after awhile. I am simply sick of starting each run freezing cold and uncomfortable. I know these negative feelings are affecting me mentally and are probably ultimately affecting my performance.

How long have you been running? Has your speed changed over the years? I’ve been running for 4.5 years – starting when I was 41. I think I peaked right before I got injured in 2010. Since that time I’ve been trying to get back to where I was.

Have you become faster or slower with age? Recently slower. But I’ll be back.

If you’re slower – why do you think? Now that I’ve done the research for this post – I think it’s a few things for me. Lack of sleep, stress, adding in speed work and increased mileage and being SICK of winter.


Fine Print: This information is simply based on my research and personal opinions. I am not a doctor or nutritionist. Get advice from a professional, not me!

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