It's safest to warm up before you try any strenuous workout. Gentle stretches, held for half a minute, can prevent injury. They feel good. They settle the mind.
Thanksgiving Day comes in just three weeks. It's one of the riskiest holidays to attempt without training. You could end up stressed and over-full and find you didn't even give thanks.
May I recommend Morning Prayer at Grace on the two Thursdays before the Big Event? It's an incredibly gentle stretch. The service has moved to a new time - starting at 7:45 in the morning. Only fifteen minutes and you're on your way to work or school or home. It'll be one of the nicest and easiest parts of your week.
Athletes also recommend stretching after a big workout. You will find Morning Prayer offered on the Thursdays that follow Thanksgiving, too, so those spiritual muscles don't cramp up.
Can't make it? No problem... that's why we're called Grace Church and not Works Church. I personally recommend commuting time - car or T - for prayer.
Try it. You'll find that when the aptly-named "Black Friday" shopping day rolls around, you're calm and ready.