Decaf coffee can keep you awake as much as caffeinated coffee, according to one study. But no other info on the Web backed that study up.
An Web search for articles on whether decaf tea keeps you awake found nothing. And herbal tea that contains no caffeine, especially chamomile, can help you sleep like a baby. You may have heard of Sleepy Time tea? It is chamomile.
But the problem in coffee and sleeplessness may not be the caffeine at all. An article titled The Great Decaf Mython The Guardian website says even decaf coffee can keep you awake :
A study suggests caffeine is not responsible for coffee's stimulant effects and that even decaf can increase blood pressure or interrupt sleep patterns for occasional drinkers.
The study into the effects of coffee found that blood pressure and nervous system activity increased when occasional coffee drinkers had a triple espresso, regardless of whether it contained caffeine.
However, those who drank coffee regularly appeared to be protected against at least some of these effects, probably because they had grown to tolerate it.
Though decaf tea hasn't been found to keep people awake, it, too, has stimulating compounds other than caffeine, including theobromine and theophylline. But the relaxing L-theanine in tea may cancel out the stimulating effects of the two theos, the effect of which is negligible anyway.
The nutritional value remains in coffee after the decaffeination process.
Theophylline and theobromine are both related to caffeine and belong to a class of organic compounds called xanthines.
They both have several physiological effects on the body.
Theophylline relaxes smooth muscles in the airway, making breathing easier while also stimulating both the rate and force of heart contractions.
Theobromine can also stimulate the heart, but it does have a mild diuretic effect and improves blood flow around the body, leading to a net reduction in blood pressure.
The amounts of these substances in a cup of tea are very small though, so their net effect on the body is probably negligible.
Some of the caffeine you ingest is metabolized into theophylline and theobromine, so every time you consume caffeine you will indirectly increase your levels of these two caffeine metabolites.
L-theanine in tea promotes 'alert relaxation'
In humans, L-theanine increases the formation of brain waves called alpha waves, which are associated with alert relaxation. This is perhaps the main reason for the different, milder buzz that tea generates.
Commonly found in tea leaves and some mushrooms, L-theanine is an amino acid that brings about a trifecta of optimal brain activity:
It improves cognitive function. L-theanine affect alpha brain waves that bring about alertness sans the jitters, heightened focus, as well as a boost in creativity. In case you’re wondering what alpha brain waves do, they bring about that state of “wakeful relaxation,” the feeling you get when you’re meditating or daydreaming. L-theanine prompts these brain waves to make you feel more relaxed and be more creative.
L-theanine is a natural anxiolytic.It eases anxiety and brings down high blood pressure. It’s a great stress reliever because it tapers down levels of hormones linked to stress and anxiety... like cortisol. While some anxiolytics such as valerian and hops reduces anxiety through sedation, L-theanine can do just the same without the latter.
At the same time, it increases the levels of calming hormones in your body. L-theanine boosts the amount of GABA, serotonin, and dopamine - all known to promote relaxation, focus and regulated mood.
The good news doesn’t stop there. L-theanine has been found to contain ZERO trace of toxicity, dependence, and tolerance. This simply means that there’s no need to worry about going overboard - you can take large doses and NOT suffer from any adverse effects.
In addition, scientific studies have found that L-theanine may help ward off cancer and reduce high blood pressure.
How much caffeine is in decaffeinated coffee?
The decaffeination process removes about 97% of the caffeine in coffee and tea. There really is a negligible amount after the beans and leaves undergo decaffeination.
That study mentioned in The Guardian does not explain why decaf coffee was found to cause lack of sleep. It is well known that some people fall asleep after caffeinatedcoffee, especially if they have built up a tolerance.
The trick to using caffeine and getting sleep
People who work the day shift are advised to stop taking caffeine after the early to mid-afternoon. The half life of caffeine is about 5 to 8 hours, depending on body metabolism, weight, etc.
So if you have a cup of coffee or some Viter Energy Mints  at 3 p.m., you will still have half the caffeine at 8 to 11 p.m.
That much caffeine may interfere with sleep. It depends on what you are used to.
If you work the night shift, you need to time your caffeine consumption accordingly.
Habits that will help you sleep soundly
If you use caffeine wisely and not too soon before sleep, you can still get a good night's sleep.
As we wrote in this blog , The World Sleep Society website  has 10 commandments of sleep that it publicizes on World Sleep Day. The site advises:
Establish a regular bedtime and waking time.
If you are in the habit of taking siestas, do not exceed 45 minutes of daytime sleep.
Avoid excessive alcohol ingestion 4 hours before bedtime, and do not smoke.
Avoid caffeine 6 hours before bedtime. This includes coffee, tea and many sodas, as well as chocolate.
Avoid heavy, spicy, or sugary foods 4 hours before bedtime. A light snack before bed is acceptable.
Exercise regularly, but not right before bed.
Use comfortable, inviting bedding.
Find a comfortable sleep temperature setting and keep the room well ventilated.
Block out all distracting noise and eliminate as much light as possible.
Reserve your bed for sleep and sex, avoiding its use for work or general recreation.
Coffee and caffeine can increase your energy and even make you smarter.
Caffeine helps burn fat.
Can significantly boost your physical and athletic performance.
Lowers the risk of Type 2 diabetes by 23% to 50%.
Several studies show that drinking coffee results in a 65% percent lower chance of contracting Alzheimer's disease.
The risk of getting Parkinson's disease lowers by 32-60% for coffee drinkers.
Cirrhosis of the liver is prevented in up to 80% of coffee drinkers.
Drinking coffee results in lower incidence of depression and can make its drinkers happier.
Coffee protects against two types of cancer, colorectal and liver, Healthline says.
Drinking coffee may lower the risk of stroke and does not appear to cause heart disease.
"For people who eat a standard Western diet, coffee may be one of the healthiest aspects of their diet," Healthline says. "That’s because coffee is quite high in antioxidants. Studies show that many people get more antioxidants from coffee than from fruits and vegetables combined. In fact, coffee may be one of the healthiest beverages on the planet."
Of course, you might not want to fill up on coffee and lattes and other caffeinated liquids, but you still want that caffeine. Try Viter Energy Mints with both caffeine and B vitamins. The tasty mints perk you up and refresh your breath.
Each has 40 mg of caffeine in a sugar-free mint, equal to about one-quarter of a mug of coffee. You can take one mint per half-hour or hour to get a steady stream of caffeine into your bloodstream, or four in quick succession to equal about one mug of java.
Viter Energy Mints energize you quickly because you can take them under the tongue, or sublingually, where the caffeine quickly enters the bloodstream, much quicker than through the stomach.
The bottom line on decaf
If you want to avoid the stimulating effects of the caffeine in coffee, tea, chocolate, energy drinks, etc., don't consume them. But it appears that most experts agree that decaf coffee and tea won't keep you awake.
I'm not sure whether the study mentioned in that Guardian has a kernel of truth. Maybe some people should avoid decaf near bedtime.
But as for me, I have a cup of caffeinated coffee around 6 p.m. every night, and sleeping is no problem.
Erectile dysfunction. In combination, those are two of the ugliest words known to man. But can caffeine help you get it up?
Science hasn't found the definitive answer to this question, but one study concluded that fewer men who consume caffeine have problems performing. The study said:
Caffeine intake reduced the odds of prevalent ED, especially an intake equivalent to approximately 2-3 daily cups of coffee (170-375 mg/day). This reduction was also observed among overweight/obese and hypertensive, but not among diabetic men. Yet, these associations are warranted to be investigated in prospective studies