I'm in week 8 of the c25k so running 28 min 3x this week. My toes start going numb around 15 min. I went back to the running store I had gotten my new Brooks from and was relieved to find out that my shoes were too small and thought problem solved so I am in a larger size and ran again today and I still had my toes going numb almost worse. I'm also 35 lbs over weight. Could this be the issue? I've never experienced this before and it's very uncomfortable/painful. Anyone have any ideas?
Are you wearing compression socks? Those might make a big difference with helping circulation and adding some additional support. It is not uncommon, but it would be a good idea to experiment with some things and maybe get a professional opinion. Many runners have problems with numb toes for a variety of reasons, so it could be a nerve compression issue (usually from shoes, a narrow toe box or overpronation, for example). You may want to even try a different brand/model of shoes and remember to rotate out shoes so you are not constantly running in just one pair.
Hope things are going better soon!
Shoelaces too tight is a common solution, but your problem sounds pretty consistent between workouts and shoe sizes, so you are no doubt reporting this problem because of a nagging suspicion that something is wrong. If you have been running for years, and lacing sport shoes for years, and never had this problem before, it could be the design of the shoe. If you are relatively new to the sport, there is a lot missing from your account that may make this one harder to solve. Let's take a look at what you've told us so far, and how you can help with some more details..
(1) You are wearing new shoes. Were these new for the entirety of C25K, or new for the recent weeks of C25K? Did the problem suddenly occur when you bought the new shoes?
(2) You "never experienced this before." Were you an active runner prior to C25K, or are you just starting out? Are you/Have you been active in other sports? For how long, and how long ago?
(3) You mentioned being overweight. Is this recent or long-term weight gain? Are you running to lose weight?
Here are some more questions that can help narrow things down..
(1) Is this problem the same in both feet?
(2) Have you ever had back pain or scoliosis?
(3) Do you work a desk job or otherwise spend a lot of time seated, as in driving?
(4) Do you walk with feet pointed forward and parallel through your entire stride, or turned slightly outward as in pronation?
Let's assume there are no anatomical or medical issues. After 8 weeks of training, it would not be unusual for one or more latent weaknesses in your running form to develop into symptoms. It's always a good idea for a new runner to get a treadmill analysis done of their running form, in order to identify common faults in form that may pinpoint anatomical/postural factors that lead to repetitive motion injuries. Specifically, if there is too much emphasis on a forefoot strike, it could lead to the symptoms you describe. It would be more likely in a heavier runner, if the weight is not reflected by a heavier musculoskeletal system.
What could be happening is a combination if things, rather than just one problem, so let's look at some of the potential risk factors..
(1) Back problems. Compressed vertebral disks in the lumbar spine can cause numbness in the lower extremities. This would be more likely if you spend/have spent a lot of time sitting, are overweight, have chronic back pain or tightness in back muscles, or a history of back injuries such as herniated disks. However, you could expect to see the symptoms in the legs as well as the feet.
(2) Elevated blood sugar. Diabetes or pre-diabetic conditions can include peripheral neuropathies generally felt in the feet and toes.
(3) Skeletal alignment. In addition to the spine above, this can include differences in hip/pelvic structure, knee joint, ankle joint, etc. Each of these can affect the other, eventually leading to nerve impingement and/or inflammation that affects nerve tissue. Slight differences in limb metatarsal length can have a dramatic effect on the health of the joints and muscles that must move to compensate and maintain balance.
(4) Foot structure. Same as skeletal alignment above, except that all final adjustments to form are eventually made by the feet. Differences in metatarsal length or tightness of ligaments, make some feet better prepared to handle this responsibility. A short first metatarsal, for example, is inherently unstable and can lead to overpronation by itself. Arch height is a combination of leg/foot structure and muscle tone. A rigid high arch absorbs little shock, while a flat arch can lead to excess motion/pronation. Hypermobile bones in the foot can also lead to excess motion. Excess motion in the bones of the foot can irritate the nerves in between the bones.
Follow Jasko's recommendations to rotate shoes not only to observe the differences, but to prevent the peculiarities of any given shoe from causing repetitive motion injuries. Even a bad shoe used once in a while may not hurt if you are not using it all the time. Also, a professional opinion will include examining joints, bones, and form for many of the problems I mentioned above. As always, when beginning an exercise regimen after a span of inactivity, it is wise to get medical clearance, which may include examination or testing for conditions that can lead to paresthesia symptoms such as numbness.