Does reading in the dark make your eyesight worse?
As kids, many of use were told that reading in the dark “weakens your eyes”. People tend to hold books closer to their face in dim lighting because of the decrease in contrast between the black words and white pages. Reading or focusing on close objects in the dark can makes the eye muscles work harder than normal to focus on images and they can fatigue. Think of it as “eye exercise”.
Ophthalmologists have found no evidence to support the idea that this extra exercise your eyes get in low light is harmful and find no evidence to support this concept. If you feel headache or nausea it might be due to staring at something relatively close to your face.
It’s safe to read in low light.
Source: Pain Doctor
Have you ever had a sharp pain in your ankles or shoulders when you were taking a walk in cold and rainy weather? Many people ascribe such symptoms to the effects of atmospheric pressure and humidity changes. When it is cold, there is higher pressure in the atmosphere. When it rains there is lower pressure and higher humidity.
There is no argument that our body’s tissues are stiffer in the cold. And this stiffness might be uncomfortable.
A study observed the joint paint of people with rheumatoid arthritis (RA) and osteoarthritis (OA). A pair of people lived in a chamber that controlled temperature, humidity, barometric pressure, air flow, and air ionization for a two-week period. Six of the eight people with RA and all four of the people with OA reported more pain and stiffness when humidity increased and atmospheric pressure was decreased. The small sample and short amount of time in the chamber make these findings interesting, but very preliminary.
There are alternative explanations for the association of weather changes with joint pain. For instance, it may be that a person is less likely to exercise when it is cold outside, and the lack of activity might contribute to joint pain.
Source: Harvard Health
Many people crack their knuckles to release tension or feel like they’re giving their fingers a stretch. The cracking results in a loud pop or snapping sound, which can be unsettling to other people. Although the science behind knuckle cracking is not definitive, the most popular theory involves a process known as bubble collapse. Bending and distracting the joints creates a space and a relative vacuum, which causes the formation of gas bubbles in the joint fluid which then pop, resulting in the cracking sound. A second and more recent theory suggests that the sound is not produced by the popping bubbles but rather by the formation of the cavity itself. There have been studies that support both theories, so it’s difficult to say which one is correct.
For some time, the practice was thought to increase the risk of arthritis. However, multiple scientific studies have shown that knuckle cracking does not increase the chance of osteoarthritis. Most of these experiments included large numbers of patients, but perhaps the most peculiar experiment was done by Dr. Donald Unger. For 50 years, he would crack the knuckles on his left hand at least twice a day while doing nothing for his right hand, and he did not develop arthritis at all, with “no apparent differences between the two hands.”