I have been practicing meditation for a month. When I sit in the cross leg posture after half an hour, my legs become numb. Is this a bad thing?
It sounds like you need to adjust your meditation position. Legs numb is not a good thing. It means there is pressure on nerves going to your legs, which could be harmful over the long term. A common mistake in meditation posture is thinking that an ‘ideal’ pose such as a full lotus pose is necessary for proper meditation. People these days spend much of their time seated in chairs so only a few people have the flexibility and body structure to sit on the floor in crossed-legged position without the use of supports. Yogananda, recognizing this problem in the West, recommended sitting in a chair for meditation. Floor sitting is also possible for many if they understand how to position correctly.
A proper meditation position is one that allows you to relax deeply but stay alert, forget the body and dive deep into peace and stillness. The essential elements are a straight spine and a relaxed body. This seat may be on a floor cushion, a meditation bench or a chair depending on what works for you. By ‘straight spine’ we mean spine erect with natural curves at the cervical, thoracic and lumbar areas preserved and balanced. When seated, the hips should be a little bit above the knees so there is a gentle curve at the lumbar spine. Tilting the pelvis with an angled pillow in the chair, an angled meditation bench or an angled pillow on the floor is often helpful. Each person may need to increase or decrease the angle to suit their body. Feet should be flat on the floor if seated in a chair as dangling feet cause tension. Shoulders should be gently drawn back to open the chest/heart area. Avoid rounding the shoulders forward, which collapses the chest area. Rest the hands with palms turned upward on the thighs and slide them back toward the junction of the thighs and abdomen which also helps open the heart area. Watch that you do not bring wrists so far back that they are bent at an extreme angle which causes pain. Head should be balanced and centered on the spine, chin parallel to the floor. Do not have the head positioned forward of the spine which can cause neck pain.
I am not able to see your cross-legged meditation posture so I will take a guess that your leg problem is due to sitting without sufficient hip-knee angle, knees possibly floating in the air rather than grounded which aggravates lower back rounding and compression of the tissues in the hip area, and possibly excessive pressure on the legs as they cross over each other. Try lifting your hips up by sitting on a higher pillow, adding folded blankets can help. Knees should drop down to the floor and lower back feel comfortable, no strain. If this does not help then you might move to a meditation bench if one is available or to a chair. For the chair you could add some hip tilt with a pillow or blanket. Be sure the chair seat is not so low that hips are level with or lower than knees. If feet are dangling you can place a blanket under your feet.
We have a 5-minute video which is part of our free meditation mini-course that shows how to sit for meditation.
The key is to keep experimenting until you find the right posture. We hope you will have a lifetime meditation practice. Bodies change over time so we need to modify meditation posture to adjust to those changes.
Many blessings on your practice,