"The best time to exercise (work out) is whenever you can” is basic advice. “What’s the best time to exercise? The best time is whenever you can find the time” we printed in Redbook magazine in April 1955. “The best time to exercise is whenever you can find the time” was printed in the book Movement Fundamentals: Figure, Form, Fun (1961) by Janet A. Wessel.

“Fitness gurus recommend working out in the morning or in the afternoon or it’s best in the evening! But all in all, the best time to work out is whenever you can” was posted on Twitter by Eric De Bie on March 31, 2018.


April 1955, Redbook (New York, NY), “How to Keep Your Family Young” by Dr. Thomas K. Cureton, Jr. with Bob Allison, pg. 31, col. 1:
What’s the best time to exercise?
The best time is whenever you can find the time. The only periods we do not recommend exercising are just after meals and right after waking up.

Google Books
Movement Fundamentals:
Figure, Form, Fun
By Janet A. Wessel
Englewood Cliffs, NJ: Prentice-Hall
1961
Pg. 115:
The best time to exercise is whenever you can find the time. 

4 November 1977, Cincinnati (OH) Enquirer, “Flabbies And Floppies Shape Of Tomorrow?” by Gregg Levoy, pg. E-1, col. 5:
Thomas K. Cureton Jr., author of Physical Fitness and Dynamic Health, emphasizes, “The best time to exercise is when you can find the time. And make it the same time whenever you do it so it becomes a habit, like brushing your teeth.”

22 July 1980, Indianapolis (IN) Star pg. 9, col. 1:
ESTABLISH A ROUTINE
Best Time To Exercise Is Whenever You Can
By Josephine Lowman
Many readers ask, “When is the best time to do my exercising?” The best time is when you enjoy it most and when it is most convenient for you, with a few exceptions.

Do any strenuous exercise either before eating or about three hours afterward. Also, in warm weather it is best not to exercise during the hottest time of the day (between 10 a.m. and 2 p.m.).

Google Groups: misc.fitness.aerobic
10PM Aerobics
RTrish
7/27/95
(...)
Work out whenever you can, just like they say the best exercise is the one you do, I say the best time to exercise is whenever you can!

Google Books
Marty’s Top Ten Diet and Fitness Strategies:
Over 100 Diet and Fitness Ideas to Enhance the Quality of Your Life
By Marty Copeland
Minneapolis, MN: Bronze Bow Publishing
2002
Pg. 159:
Many people have asked me, “When is the best time to exercise?” My answer is, “Whenever you can.”

Google Books
The Schwarzbein Principle, Program:
Losing Weight the Healthy Way
By Diana Schwarzbein
Deerfield Beach, FL: Health Communications, Inc.
2004
Pg. ?:
The best time to exercise is whenever you can.

Google Books
The Fiber35 Diet:
Nature’s Weight Loss Secret
By Brenda Watson
New York, NY: Free Press
2007
Pg. 112:
One question I hear frequently is this: When is the best time to exercise? To that I say, “Whenever you can.”

Twitter
Shilpa Tushar Shah
@ImShilpa1963
What’s the best time to exercise?
Whenever you can make it a part of your routine…
Research shows that your body will adjust to whatever time of day works for you…
The most important thing is to pick a time of day you can stick with...👍👍
3:31 AM - 16 Jan 2018

Twitter
Eric De Bie
@BieEric
Fitness gurus recommend working out in the morning or in the afternoon or it’s best in the evening! But all in all, the best time to work out is whenever you can. If you exercise at different times of the day, be sure to note the hour as you’re tracking your progress. #weightloss
4:00 PM - 31 Mar 2018

Twitter
Tony Jacobsen
@iamTonyJacobsen
I’m often asked, “When is the best time to exercise?” The answer is simple, “Whenever you can get it in!”
For me, it was a quick squat/push-up/balance session before starting my day.
#workout #disableyourdisability #osteogenesisimperfecta #brittl… https://ift.tt/2J3Hsyl
4:57 PM - 2 Jun 2018

Twitter
Nikki
@GetFitWithNikki
People ask me quite often 👉 “when is the best time to workout?”
The short answer: “whenever you can get it done!”
There is no right or wrong. Just do you! Workout whenever it fits best into your day and/or you… https://www.facebook.com/FitWithNikki/videos/2247895731917764/ …
9:58 PM - 10 Jul 2018

Women’s Health
What’s The Best Time Of Day To Work Out?
Morning? Afternoon? Evening? Does it even matter?
By Kristin Canning and Hayley Shapley
Aug 14, 2018
(...)
But when it really comes down to it, the answer is pretty simple: The best time to work out is whenever you can do it.

Twitter
Michaela
@moonphoto01
The best time to work out is whenever you can do it
7:26 PM - 3 Jun 2019