Thirst: Our brains tell us when to stop drinking

When the water content of our blood drops, neurons in the brain tell us that we are thirsty. But how do we know when enough is enough?

Water is essential to life. When we get deydrated, it can have serious consequences.

The water content in our body is tightly regulated. Dehydration can lead to dizziness, delirium, and unconsciousness. Drinking fluids restores this balance or homeostasis.

But it takes time for water to travel from our mouths through the body. We stop drinking a long time before this happens.

If we kept drinking during this delay, we would be at serious risk of water intoxication, or water poisoning, which is potentially deadly.

Scientists are beginning to unravel the sophisticated mechanisms that stop us from drinking too much water, and the answer lies in the brain.

What controls thirst?

The brain’s thirst control circuit is a small region in the forebrain called the lamina terminalis (LT).

Once the LT network is activated, we become thirsty. A study published last week in the journal Science demonstrated that thirst creates an uncomfortable feeling in mice, which is alleviated by drinking.

There is one other thing that triggers thirst: eating. As soon as we start to eat, our thirst is stimulated. This is known as prandial thirst.

Water is necessary for us to digest the food that we eat. It also stops electrolytes in food from disturbing homeostasis by balancing out the fluid levels.

Why do we stop drinking?

Zachary A. Knight, Ph.D. – from the Department of Physiology at the University of California, San Francisco – and his team reported in the journal Nature that neurons in the subfornical organ (SFO), which forms part of the LT, might be at the heart of things.

The authors explain that “much normal drinking behavior is anticipatory in nature, meaning that the brain predicts impending changes in fluid balance and adjusts behavior pre-emptively.”

For their study, the researchers used mice and restricted their access to water overnight. “When water was made available,” the authors write, “mice drank avidly and, surprisingly, [SFO] neurons were inhibited within 1 min.”

This drop in neuronal signaling happened much faster than the water was able to reach the blood.

“Drinking resets thirst-promoting SFO neurons in a way that anticipates the future restoration of homeostasis,” they add. This means that our brain anticipates how much water we need to drink to restore homeostasis.

Signals from the mouth to the brain

What is not yet clear is how the brain knows when we are drinking fluids. A recent study published in the journal Nature Neuroscience pointed the finger at receptors in our mouth.

The team – led by Yuki Oka, Ph.D., who is from the Division of Biology and Biological Engineering at the California Institute of Technology in Pasadena – showed that water changes the acid balance in the saliva, which activates acid-taste receptors.

So, what is the best way of quenching thirst? A study by Sanne Boesveldt, Ph.D. – from the Division of Human Nutrition at Wageningen University & Research in the Netherlands – and her team, which will be published in the October edition of the journal Physiology & Behavior, set out to answer this question.

The authors explain that cold drinks are already known to be more thirst quenching, as are sour, flavored, and carbonated drinks.

In their study, the team found that cold, flavored popsicles were significantly more thirst quenching than cold liquids. The most effective flavor was lemon.

So, while the days may be getting colder as fall gets underway in the Northern hemisphere, a lemon popsicle might still be a good option the next time thirst calls.


It’s Not Aging: 5 Other Reasons You Have Forehead Wrinkles

Before you sound the alarm, here are five things — not related to aging — that your wrinkles are telling you.

Dread. That’s often the first feeling people describe when they talk about forehead creases — and according to researcher Yolande Esquirol, there might be a valid reason to make a check-up appointment with the doctor.

In his recent, although unpublished, study, Dr. Esquirol suggested that the deeper the forehead wrinkles, the higher the risk of cardiovascular disease.

The study, which followed women 30 to 60 years old, over the course of 20 years, found that “minimal to no wrinkled skin” (a score of “zero”) carried the lowest risk.

However, a score of “three” carried 10 times the risk of cardiovascular disease. The theory is that the blood vessels around the forehead have plaque build-up, causing deepened, hardened wrinkles.

But before you sound the alarm, know that science has yet to prove that this is the case. Plus, removing your wrinkles isn’t the answer to preventing heart disease. (We wish it were that easy.)

Currently, anecdotal evidence suggests that the more likely connection is this: deep forehead wrinkles are a reflection of lifestyle factors (age, unhealthy diet, stress, etc.) that contribute to higher cardiovascular risk.

There’s also a lot of other reasons you may be getting wrinkles — and ways to prevent them from getting deeper.

(Also, let’s take a moment to acknowledge this, yes, cadaver-based study — because the dead don’t lie — found no correlation between wrinkle depth and the ages 35 to 93.)

Here’s what having wrinkles most likely means, by the decade.

If you’re in your 20s to 30s…

Step off the retinol immediately (once you go to too high a percentage, it’s really hard to go back) and take a look at your environment. Are you wearing sunscreen? Moisturizing enough? Exfoliating once a week? How’s your life?

Research has found that external and internal stress can cause detrimental “formations” in one’s skin. That’s everything from the pressures of nailing that new job interview to the metropolitan pollution wreaking havoc on your skin in the form of acne or slight wrinkle formation.

Try this: As the Brits say, “Keep calm and carry on.” Work anti-stress relievers into your routine. Try daily morning meditations, posture exercises (stress can change the way you carry your body), or changing up your diet.

Another recommendation includes brewing homemade tonics to bring back the pep in your step and checking out this simplified skin care routine.

If you’re in your 30s to 40s…

The early 30s is still a little too young to be dabbling in stronger chemicals. Save your money on retinols and retin-As and consider a light chemical exfoliation with face acids.

Dead skin cells can build up and darken the appearance of wrinkles. You may also want to invest in some vitamin C serums, if you haven’t yet.

Of course, skin approaching its 40s can be significantly less hydrated. So, on top of exfoliation, be sure to moisturize with a night cream and drink plenty of water every day for the rest of your life. Both work in the effort to pop elasticity back into your skin and reduce wrinkles.

Try this: Aim to drink eight glasses of pure water per day. After sunscreen, hydration is the next most important step to letting your skin achieve that crème-de-la-crème texture.

As for face acids, take a look at our handy chart below. Some acids, such as lactic acid, can provide moisturizing effects. Or make sure to buy products that contain hyaluronic acid.

If you’re in your 40s to 50s or beyond…

This is about the time to pop over to a dermatologist and check out that gold-standard retinoid you’ve been hearing about (start low!) — especially if you’ve completed the checklist of addressing your mental health and skin health.

Another factor you should consider is a change in your environment or lifestyle habits. Has the weather shifted? Is your office ventilation questionable? Are you traveling more on airplanes?

Skin in your 40s to 50s can be significantly less hydrated and produce less sebum, meaning it’ll be more reactive to environmental changes and stress.

The 40s to 50s is also when most people really feel the hormonal change taking a physical toll on their body. You may notice weight gain or limited flexibility. Your 50s is also when it’s time to reevaluate your diet and exercise habits as your risk for cardiovascular disease also increases.

Try this: Sit down, take a breather, and see if there are any changes you can make to support your body. Consider eating more anti-oxidant foods (or following our shopping list). Invest in a heavy-duty moisturizer and travel-size rosewater spray.

We also recommend dermarolling to get your collagen production up. If you’re still not seeing changes and want to go to more serious depths, ask your dermatologist about laser treatments like Fraxel.

If you’re in your 50s to 60s…

Now is the time you may want to consider checking in more regularly with the doctor about your heart health.

It’s not a bad idea to visit your doctor, as cardiovascular disease can be prevented with the right lifestyle changes: a healthy diet, active lifestyle, controlled blood pressure, and keeping in mind your family history.

Try this: If the wrinkles really have you concerned, know that it’s not a heart-health condition and that you can remove them! While topical products might not work as well as they did for you in your 20s, a dermatologist can recommend more technologically advanced tools (lasers, fillers, and stronger prescriptions).

The forehead wrinkle checklist:

  • Mental health. Are you extra stressed, depressed, or anxious?
  • Skin hygiene. Are you cleansing, exfoliating, and sun screening properly?
  • Skin hydration. Are you drinking enough water and moisturizing?
  • Weather change. Are you accounting for the humidity or dryness in the air?
  • Lifestyle factors. Are you eating a heart-healthy diet, exercising regularly, and getting check-ups?

While the number of wrinkles may cause others to think you are older, keep in mind that there’s no reason to be erasing them unless that’s what you want to do. After all, science does say, the older you are, the happier you’re likely to be too.

Find Nurse Solomon on his Twitter Handle sol@Mpanga

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Staying Healthy And Fit

How To Stay Fit

What can I do to get more fit?

Any type of regular, physical activity can improve your fitness and your health. The most important thing is that you keep moving!

Exercise should be a regular part of your day, like brushing your teeth, eating, and sleeping. It can be in gym class, joining a sports team, or working out on your own. Keep the following tips in mind:

  • Stay positive and have fun. A good mental attitude is important. Find an activity that you think is fun. You are more likely to keep with it if you choose something you like. A lot of people find it’s more fun to exercise with someone else, so see if you can find a friend or family member to be active with you.
  • Take it one step at a time. Small changes can add up to better fitness. For example, walk or ride your bike to school or to a friend’s house instead of getting a ride. Get on or off the bus several blocks away and walk the rest of the way. Use the stairs instead of taking the elevator or escalator.
  • Get your heart pumping. Whatever you choose, make sure it includes aerobic activity that makes you breathe harder and increases your heart rate. This is the best type of exercise because it increases your fitness level and makes your heart and lungs work better. It also burns off body fat. Examples of aerobic activities are basketball, running, or swimming.
  • Don’t forget to warm up with some easy exercises or mild stretching before you do any physical activity. This warms your muscles up and may help protect against injury. Stretching makes your muscles and joints more flexible too. It is also important to stretch out after you exercise to cool down your muscles.

Your goal should be to do some type of exercise every day. It is best to do some kind of aerobic activity without stopping for at least 20 to 30 minutes each time. Do the activity as often as possible, but don’t exercise to the point of pain.

A Healthy Lifestyle

In addition to exercise, making just a few other changes in your life can help keep you healthy, such as

  • Watch less TV or spend less time playing computer or video games. (Use this time to exercise instead!) Or exercise while watching TV (for example, sit on the floor and do sit-ups and stretches; use hand weights; or use a stationary bike, treadmill, or stair climber).
  • Eat 3 healthy meals a day, including at least 4 servings of fruits, 5 servings of vegetables, and 4 servings of dairy products.
  • Make sure you drink plenty of fluids before, during, and after any exercise (water is best but flavored sports drinks can be used if they do not contain a lot of sugar). This will help replace what you lose when you sweat.
  • Stop drinking or drink fewer regular soft drinks.
  • Eat less junk food and fast food. (They’re often full of fat, cholesterol, salt, and sugar.)
  • Get 9 to 10 hours of sleep every night.
  • Don’t smoke cigarettes, drink alcohol, or do drugs

Hoping This Article Serves You well.

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Thank you so much

-Your Nurse Solomon

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