A classic symptom of lumbar spine stenosis is that your back hurts with prolonged walking or standing AND your back pain goes away when sitting.
Lumbar spine stenosis generally occurs in a middle aged or older person. This is because as we age our discs lose fluid. Thus, the spacing between our vertebrae narrows causing foraminal stenosis effecting the spinal nerves as the nerve leaves the spine or central canal stenosis, effecting the spinal cord. Furthermore, the older spine also develops bone spurs and narrowing of joint spaces...
How should you exercise if this is your issue? If working on your cardio, it would be better to bike or swim than to walk. However, if you insist on walking, you should break up your walk with periodic sitting on a bench.
Generally, flexion or rounding of the spine will open up the spinal spaces so Angry Cat Stretch or Double Knee to Chest Stretches should be great for you.
It can get tricky if your are trying to strengthen your back muscles. Often these exercises are done while lying flat on your stomach.
If you have lumbar stenosis, lying on your stomach may be painful and lifting an arm/s or leg/s and or torso may further increase your back pain. You could try to place one or two pillows under your stomach to ease the pain during these exercises. The placement of the pillows under your stomach moves your spine out of spinal extension to a more flexed position. Thus, you are better able to lift your arms, legs or torso without going into as much spinal extension. The image below is of my Mom doing a supported back strengthening exercise with the patented MINIMAX.
This issue of pain with exercising while on your stomach is one of the reasons I developed the MINIMAX. The MINIMAX offers three different ways to lie on your stomach: from the slope side (as pictured), from the rounded end or across its width.
Please reach out if you have any questions. It is so important to keep exercising but sometimes you have to modify exercises so that you can continue to do so without pain. Please share this information, if you found it valuable...Thanks!