Why am I so much slower (35+ sec) in morning workouts?

I actually do a lot of my runs in the middle of the night. I wake up at around 2pm, despite all the sleeping pills consumed before going to bed, get up and have a cofee, find I don't feel sleepy any more, so I nip out to get some miles in. If it's less than 5 miles or so and cold weather, I'll keep my dressing gown on.

I notice that my heartrate is up and my pace is up to a minute slower during these middle-of-the night runs. Is this the same for everyone? Can anyone explain what is going on?

I'd say this is pretty normal. The body needs its time to gain momentum.

When I have to run in the morning, I start with Yoga to become flexible, then drink my tea.

But still, I'm slower.

I also notice that I run slower in the dark, regardless morning or evening.

A person's levels of Cortisol (a stress hormone) are usually elevated in the morning.

I have the same issue, and I tend to race a hell of a lot better in the afternoon/evening than in the mornings.

It's super annoying that just about every road race is put in the early morning though.

I run at 5 am before work and it’s the same for me. I wake up, get dressed, have water and I’m out the door. And I’m slower. Warmup helps but I’m still slower.

Late morning or afternoon runs in the weekend, I feel much stronger, quicker.

I haven’t found out how to fix it except for big races, that start at 7 am, I get up 3 hrs before, have coffee, eat and let the body wake up. That helps.

While I understand and agree with this, I would have expected that if my body doesn't have "momentum" yet, then I would also struggle to get my heart rate up. Ie, I could only tempo at 5:50 pace, but my HR would be around 150, not 170, as that's all the oxygen my body needs to run at that tempo

I am very similar and have put it down mainly to flexibility - or lack thereof - in the morning. When I wake up I was substantially more tight and rigid compared to later on in the day. When I first wake up I cannot get my hands below my knees if I try to touch my toes and by the evening I am probably a good 3 inches further down my shin. Translating this into running, if you are physically really tight then running fast - which requires a greater range of motion - will be very much harder!

Just my 2 cents.

I've found the same thing to be true but not quite that drastic. If I usually do my easy runs @ 6:45-7:45 pace @ 7 or 8am. I'm usually more like 8:00 pace if I roll out of bed into it at 5 or 6am on an early day. It takes me a lot longer to get down to 7:00ish. Usually I get there by the end but I don't force it on those days. Like you said, the body just doesn't work the same when your routine is a little off.

I don't usually do workouts on those days but 45s/mile on a tempo seems a bit much after a warm up. There might be something else happening here. I would make sure to try to sleep a little earlier on workout days like that and would maybe try some caffeine.

Another point to ponder: am I still getting the same workout effect, even though the quality is so low, as my heart rate is still in the right zone?

Either run comfotably fast or comfortably slow. That's quality training and good recovery running.

If you have to race in the morning, you are going to have to do enough of a warm up to get the adrenaline going to put you in the right zone for your best performance.

Since the dawn of time, results have shown that races in the evening, produce faster times than races in nthe morning. Multitude of reasons.

Probably, yes. You can't force something that's not there at that moment in time. Plus, if you're using heart rate to guide you, then use it. By that I mean, stay in the desired zone and allow your heart rate to tell you what that is, at that moment in time. Maybe for early morning runs, you use heart rate zones and later in the day, pace zones, if that's what your body is telling you it needs. Or, ignore both and go by RPE (relative perceived exertion).

Either way, realize you're not the only one whose pace sucks when you're trying to run half-asleep, uncaffeinated, on an empty stomach, when it's balls-cold.

Are you eating/consuming anything before you head out the door?

Running in a glycogen depleted state can have an impact.

Agreed. Let's have more afternoon/night road races. Friday nights would be perfect for most hobbyjoggers and sub-sub-elites. People are more likely to socialize after the race, and you can sleep in Saturday morning.

Maybe the heart is still busy waking and warming up other parts of the body. You could also be running more inefficiently without realizing it because of subconscious differences in neuromuscular firing.

I am surprised that this has not been brought up yet. The fasting during the sleep time (and typically a few hours before bedtime) will leave your glycogene stores halfway empty by the time the alarm rings. If you have not had breakfast yet then its normal that you do not have the same energy as fully fuelled. Even when I run right after waking up I always eat minimum a banana or something of equal quantity before heading out and it makes morning runs substantially easier.

I'm also slower in the mornings. Even well rested, stretched, warmed up etc.

Though I think it mainly has to do with the limited daylight. Lots of studies show that with limited peripheral vision, the eyes and brain have difficulty gauging how quickly you are (or are not) moving past your surroundings. Food for thought.

because you're scared of tripping - same happens to me

Definitely. That's why I started using a headlamp for early am runs in the dark. Even though my route has partial lighting in some areas, it gives you more confidence to go fast knowing you won't trip on a pine cone, tree branch, rock or curb.

this is classic glycogen issue.

i have the same problem. I could train like a sub 25 8K runner, but come race morning could never go faster than 5:20 pace (regardless of the distance). If workout were in the am I would suck compared to others, but move that workout to the afternoon or evenings - different story.

I did not have this issue when younger. Wondering if age is playing a big role here.