Halacha tells us that there are certain activities that are forbidden to do before one davens the morning prayer. Would exercise be one of those activities ?
1 Torah Musings says
Minor activities are not considered to be work, nor a fulfillment of one’s own desires, and they are therefore permissible before prayer. For example, a person is permitted to make his bed before praying, and he is permitted to take the garbage from his house to the public garbage bin. Similarly, he is permitted to read the newspaper a bit and do a little exercise before prayer.
(No source given).
The Shulchan Aruch (OC 89:3) says that it is forbidden for a person to involve himself in his own needs before davening. This certainly includes eating and drinking before davening which Chazal say is an expression of haughtiness; exercise is a grayer area. The Rema (ibid) though adds though that there are those that are lenient in this matter if the person has said some of his Berachos.
If the exercise is being done for health maintenance (and not for pleasure) and it is difficult to do it after davening, then it is seems there is room for doing it before davening provided that the person says Birchos haShachar before hand.
Kol Tuv, Yonasan Sigler *This is not meant to be a Psak Halachah.
3) israel.aish.com (Review Sheet for The Times of Davening - (Orach Chaim:Siman 89, 232-234)
a) If a person needs to exercise before davening in order to have strength to serve Hashem and he can’t do it later then this is also Maleches Shamayim.
Conclusion: Minor exercise is permitted. If it cannot be done later, then exercise for health (after saying brochos) or to have strength to serve Hashem is permitted.