I find it best to find my own pace. A speed where I feel comfortable breathing and don't get any cramps or aches. If you have a hard time keeping up with the breathing you are probably going too fast. I recommend a trial and error approach where you try different speeds and find one that you feel you can handle steadily without having to stop or slow down for at least 20 minutes. Eventually you will work yourself up to faster and more demanding speeds as your endurance improves. It also helps me a lot to do a one kilometer brisk walk warm-up. Hope this helps.
As long as you don't have medical problems, you can use the cardiovascular recommendations on line for cardiovascular work out which is related to age and pulse (heart rate) or look for guidelines on building strength versus muscle mass. all have different guidelines, and you don't indicate your specific goal.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. Med Help International, Inc. is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.