Why Italians don't drink cappuccino after noon

Middle of July, suffocating heat and humidity, Sunday lunch time. I am about to pass out and start fanning myself with my hand and start breathing shallow. Our host asks if we would like the fan turned on. I nod with gratefulness on my face. They turn a little fan on on the lowest setting in the other side of the long dining room and turn the head of the fan towards the wall.

August, scorching heat outside, going in the car. We have all windows down completely. But then our passengers are cupping their ears with their hands, they are wrapped up in a big scarf and to our question of whether they want the windows up a little they gratefully nod.

After one year in Italy I have learnt that there was one thing that many Italians feared above all others: "il colpo d'aria", literally, "the hit of wind". It is said to cause a mysterious condition called cervicale, a kind of neck pain. Our Italian friends swear that they had all experienced it.
Protecting yourself against the "colpo d'aria" is just one way you're meant to watch your health in Italy. But if locals are to be believed, there are many  other ways to fall ill, too -including air-conditioning, drinking a cappuccino after dinner, or leaving the house with wet hair.

I had found some information on these cultural ideas and believe it or not some of these actually have medical basis according to doctors.

1) The "hit of wind" can give you something called cervicale.

Turns out, there is something there. Getting a "hit of air" can't make you sick in terms of giving you an infection or a cold, said Dr.Steven Lamm, an internist and the medical director of the Tisch Center for Men's Health at the NYU Langone Medical Center. But being suddenly chilled  - whether by a cold breeze or from suddenly entering air-conditioning - does make the body work harder to maintain its 98.6 degree temperature. "The body is being forced to make adjustments. That process could result in some mascular cramping, or mascular spasms", Lamm said.
Hm. That would explain why...

2) You should never leave your house with a wet head

Ever.
I went out with a wet ponytail before, usually just popped over to the bakery. I am warned every time how I would get sick. Even if it was 75 degrees out.
According to doctors the idea probably stemmed from the same as above: it is not smart to go outside in the freezing weather with wet hair because you're stressing out your body slightly.
And of course the wet-rat look ruins la bella figura.

3) Having a cappuccino after dinner inhibits digestion.

You should follow dinner with an espresso, never with a cappuccino. A cappuccino, instead is always drank before noon, usually at breakfast. They say dairy, consumed after a meal would inhibit digestion and make you feel discomfort.
According to doctors, it doesn't actually inhibit digestion, but could make you feel discomfort. Why?
It is estimated that about 80% of adults lack the enzyme that metabolizes milk and dairy. "If someone has a big meal and then has a glass of milk, whether it's in a cappuccino, or just in itself will have some gas."-said Dr.James Marion, a gastroenterologist at Mount Sinai Hospital. It doesn't inhibit digestion, but one might notice they don't sleep as well, whether because of the caffeine, the milk, or the sugar, or because they feel bloated.

4) Sparkling water helps digestion

It's little wonder that a culture so in love with food is also so concerned about digestion. It is a widespread idea that sparkling water helps digestion and you find a bottle on every dinner table in Italy. Dr. Marion pointed out that carbon dioxide has no digestive properties, however sparkling water could help make you feel slightly less full: the gas makes you want to burp, and burping relieves pressure. When it comes to digestion, though, you're better off not having eaten that heavy meal to begin with. :)

5) Air-conditioning makes you sick. 

Dr. Lamm says "there are medical conditions that are associated with air-conditioners. They're primarily the result of the fact that air-conditioners require water to be recirculated, and the water can promote the growth of mold and infections." For that same reason, in some buildings with central air-conditioning, people get sick more often having allergic reactions with symptoms like shortness of breath and wheezing.
So yes. Make sure that filters are clean and when possible, use fresh air instead.