What A Difference Good Sleep and Diet Make

We all know that rest is important and that if your sleep suffers – so will your running. But how much difference do sleep and diet really make?

Well last month I went away for a few days for work and I found out. As I reflected on the impact of poor diet and sleep on my running those few days, I thought it would be useful to share this little story.

Setting the Baseline – Before the Trip

I’m a consistent runner. I’ve put in 60-70 miles every week this year, and 40-50 most weeks last year. So I have a good idea of what I’m typically capable of.

Throughout the spring and summer, my easy pace has been around 8:30 to 9:15. On a good day, I’ll warm up and eventually fall into a groove somewhere in that range.

The morning I left for my trip, I ran 12 miles. I had 17 miles planned for the day, but I really didn’t want to do a long run right before I hopped on a plane. So I split it up into a 12 mile run in the morning and a 5 mile run once I got situated.

I woke up that morning and it was raining pretty bad. So I started my run on the treadmill. After about 40 minutes, I went upstairs for a quick bathroom break. I noticed the rain had let up to a light drizzle, so I decided to finish the last 8 miles outside.

I ran down the street to the Orange Reservoir Loop, made a few laps, and came back home. My legs were already warmed up, so from the get-go I was running around 9:00/mi. Over those 8 miles, I averaged 8:58/mi.

It was towards the slow end of my typical pace, but well within what I would call normal.

Running in Rosement on the Trip

Later that morning, I hopped on a plane to Chicago. I was attending a conference in Rosement – right by O’Hare Airport.

I would be there from Thursday afternoon until Sunday afternoon. So the plan was to put in a short run (5 miles) after I checked in Thursday night, and then do my usual 8 mile run every morning from Friday to Sunday. I pushed my typical Sunday long run off until Monday, because there was no way I would get the miles in and make it to the first conference session on Sunday.

I checked into my hotel, and thanks to some research I knew that there was a nice running trail near by. After a change into my running clothes, I jogged over to the Des Plaines River Trail and Greenway. There’s an entrance right by the Hyatt Regency, and from there I had access to miles and miles of trails.

I put in my five miles, and everything went well. It was hot – about 90 degrees and sunny. But the trail was shaded and the humidity wasn’t too bad. Even with the weather, and having already put in a good run that morning, I averaged 9:08 per mile.

That night, the festivities began. We had deep dish pizza and a few beers. I got back to the hotel at a decent hour, but I had to be up around 6 the next morning. After a big late night meal, my sleep quality wasn’t great.

My body battery only reached 24 by the time I crawled out of bed. I was out the door in 15 minutes and running back to the trail. Read more about how body battery is calculated here.

But this time, things didn’t go so well. I had to back off the pace quite a bit, and I averaged 10:23/mi.

The pattern repeated itself over the next few days. I was walking around the conference, so I had little time to rest during the day. We had dinner late at night, and I probably ate more than I should have. But a little gluttony is ok, from time to time. As a result, my sleep suffered, and I woke up before 6 to make sure I could get my miles in.

My body battery graph looked similar on Saturday and Sunday, and my runs only mildly improved. Saturday morning, I averaged 10:07/mi, and Sunday I was blazing fast – 9:41/mi.

Back Home After a Good Rest

There’s no question that a few days and nights of constant activity, late meals, and poor sleep left me drained. This had an impact on my running performance – although I did manage to get the miles in.

Part of me wondered if there was another explanation. I did recently get over COVID, so I wondered if that was hindering my performance as well. People often struggle in the weeks after they recover.

I’ve also been increasing my mileage as part of my base training prior to starting my next marathon block. The week that ended with my trip was my first week at 75 miles, and the previous two weeks had been at 70. So it’s possible the cumulative fatigue was getting to me.

I got home from Chicago on Sunday night. It wasn’t too late, and after I spent a little time with the family I was knocked out in bed a little after 11pm. I slept soundly until 8am. I then had an our to leisurely sit in bed sipping my coffee before I went out for my run. My body battery peaked at 81 – the highest it had been since before the trip.

I went out for a ten mile run, and I felt great. My first two miles were a little slower as I got warmed up. The next five, I averaged 8:30/mi, and it felt very easy. I decided to push it a little bit for the next two, and sped up to 7:55 and 7:39. Then I backed off fo the last mile to cool down as I headed for home.

Just like that, I was back. The difference between that run and the three previous runs in Rosemont was like night and day.

Lesson Learned – Rest Well

So how much difference does good rest and diet make? Quite a bit.

In my case, a few days of overeating and poorly sleeping led me to struggle through runs a full minute slower than my typical easy pace. But with just one good night’s sleep, I was feeling a lot better and back in form.

So the moral of this little story is simple. Rest well. Don’t eat a ton, and don’t eat too late. Don’t drink too much, if you want to have a decent run the next day. And if you’re waking up early to get your run in, expect to be a little slower than you normally would be.

But, the good news is that any effects are short term. If it’s only a few days of bad habits, you can expect to have a few bad runs but get back to form quickly with one or two days of recovery. So plan accordingly, and make sure that you rest well before important workouts and races.

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