My calendars always consider Monday as the first day of the week. I began tracking my weeks this way as a convenience, and have kept it up that way because it made planning and analyzing my workouts so much easier. My wife disagrees with me and thinks that it makes more sense for the week to start on Sunday.

From a training stand point, I find that it makes much more sense to consider Saturday and Sunday as part of the same week. In general, most of the races that I compete in are on Sundays, with Saturday taking the bulk of the remaining races. On weeks where there is no race, the majority of my long runs will take place on the weekend. By putting Saturday and Sunday in the same week, I can plan my workouts leading up to those two days. I can then consider them as one unit and best decide how to utilize the two days that I generally do not have to work and will have the most time available to get in quality workouts and races. It allows me to have a set Monday through Sunday schedule for considering my weekly mileage.

Let me illustrate why this matters with an example. Today is Sunday. Suppose that I run 18 miles today for my long run. My mileage during the week is fairly stable and is the same as it was the week before. The next weekend, I know that I will not have time for a long run on Sunday, or else I can have company on my run on Saturday, so I decide to do my long run then. Two weekends from now, I am back to running long on Sunday. If my weeks ran from Sunday through Saturday, then it would seem as though I had an average mileage week, a super high mileage week, and then a super low mileage week (comparatively speaking).

Looking at my training logs, I would need to fudge the numbers to see that in reality, I had a few weeks in a row that were fairly stable mileage-wise. It would probably be time for me to have a cut-back week and get a little rest, but looking at the numbers it would seem as though I just had one.

Now consider the same scenario with my week beginning on Monday. It would seem as though I had 3 weeks in a row of similar mileage, and I would determine that I need to either increase or decrease the mileage depending upon how I felt and where I was in the season.

Splitting the weekend into two separate entities just never made much sense to me. Other than the Boston Marathon, most of my races fall between Friday evening and Sunday morning. In most cases, I can equate the week of a race’s mileage with how I prepared for the race. If I started my weeks on Sunday, then I would have to remember up to a year or two later whether a race fell on a Saturday or a Sunday in order to be able to tell at a glance whether the mileage I ran the week of a race came before or after the race.

The largest inconvenience caused by not considering Sunday the first day of the week is that most existing calendars do put Sunday at the start. I do not use regular wall calendars for my training logs, and most of the time when I need a calendar it is when I am using a computer. Most of the systems that I use support either day as the first day of the week, which makes it only a small disruption for myself.

Which day begins your week? Have you ever given it any thought, or have you always picked on day over the other? Do you consider Saturday the first day of your week? Let me know what you think and why. If you do consider Sunday the first day of the week, are you thinking of changing your mind? If so, you should give it a try. You can always switch back.