In his new book, A Short Guide to a Long Life, David B. Agus, M.D., whose patients have included Neil Young, Steve Jobs, and Sumner Redstone, offers bite-sized, straightforward advice on living longer and better. See seven of his tips below.

1. Get naked

We throw our clothes on and off daily, during which time we’re partially or wholly naked for a few seconds or minutes, and we spend quality time in the shower in our birthday suit. But when was the last time you took a good look at yourself butt naked in front of a mirror—front and back? You’d be surprised by how illuminating this exercise can be. You can spot trouble on the horizon in the form of body oddities that you didn’t have before and signs of skin cancer.

The skin acts as an indicator of the state of the entire body, and external skin discolorations, blemishes, lesions, rashes, blotches, or other unsightly marks can be signs of underlying internal disease. Once in a while, take a visual inventory of every square inch of yourself, including your hair, nails, and the inside of your mouth.

You can also get an honest sense of how well you are aging based on your physical appearance alone. Is your overall skin tone and set of wrinkles reflective of someone your age? Do you look older than your chronological age? And you can use this moment to gather measurements that can help you track the progress you’re making by changing your habits. Measure your waist and see it get smaller. Start a skin-care routine that nourishes the health of your skin (and keeps you examining your skin regularly).

Or maybe just tell yourself that you’re beautiful and doing okay. Say an affirmation as you stand there naked and accept who you are. We all know that having a strong sense of self and being comfortable in our own skin will go a long way to keeping us healthy and psychologically strong.

2. Strengthen your core and maintain good posture

You can tell a lot about someone just by looking at the way he carries himself. Is he hunched over like an old person? Does he slouch with his head down as if he is depressed? Or is he walking fully erect, chest up, as if he is ready to take on the world with a smile on his face? With the right posture, anyone can appear younger, thinner, and more confident. But these effects aren’t just for vanity’s sake. Maintaining correct posture may be one of the best-kept secrets for achieving a longer, healthier, and more enjoyable life.

We know that poor posture can lead to a wide assortment of neck and back problems. It is often caused by a weak core, which is one of the primary risk factors for back problems—at every age. Poor posture can also cause headaches, TMJ, arthritis, poor circulation, muscle aches, difficulty breathing, indigestion, constipation, joint stiffness, fatigue, neurological problems, and poor physical function in general.

But the risks don’t end there. It’s well documented that people with what’s called hyperkyphosis—a posture that’s hunched over, with the head and shoulders rolled forward—are 2 times more likely to die from pulmonary problems and 2.4 times more likely to die from atherosclerosis (a disorder characterized by a narrowing and hardening of the arteries due to plaque buildup) than those with normal posture. What’s more, these individuals are 1.44 times more likely to die of any cause than those with healthy posture. Even people with a mild degree of hyperkyphosis are likely to die sooner.

Bear in mind that posture also plays into our emotional state. Because posture is often linked to our facial expressions, it can subconsciously drive our emotions: when we stand tall and erect, we exude confidence. This in turn helps us to feel good about ourselves and have an optimistic outlook. All roads to perfect posture start with a sturdy core. You don’t need a chiseled six-pack, but engage in exercises that work this area.

3. Mobilize your medical data

Do you have copies of all your medical records, and are they accessible online somewhere? Why not? What if you land in the emergency room and cannot talk but have a potentially fatal allergy to penicillin—the very drug a doctor is about to inject into you?

We use our phones and computers today for just about everything, with one exception: storing our medical records and keeping our health information updated. Aim to have all your records stored in your “mobile cloud” so they are always accessible to you. Give a trusted family member (spouse, parent, sibling, adult child) or friend your passwords so they can access those same files when and if it becomes necessary. Everyone needs a partner in health care. Pick someone. Give that person full access to all of the places where you keep your medical data.

If you don’t have your medical records nicely organized in digital files, request copies of your files from your doctors. Spend a weekend afternoon creating digital copies of them using a scanner. You can also keep them on a USB key chain that you take everywhere. This task may sound daunting, but it’s just a few hours of work from which you can benefit for the rest of your life. It is unusual that patients of mine have a medical emergency between the hours of 9:00 a.m. and 5:00 p.m. when the office is open and we can access their records. Problems always seem to happen in the middle of the night, on a weekend, or when someone is traveling! We each have different health profiles, but that distinctiveness can present a challenge to doctors who don’t know anything about us, yet have been given the job of treating us. Having your entire medical record on file to hand over just might save your life.

4. Have a glass of wine with dinner

Habits that transcend culture and religion and date back thousands of years probably have some benefit to them regardless of what the science says. But now we know that moderate alcohol intake, especially from red wine, can reduce one’s risk for heart disease. This benefit does have a caveat, however: drinking can potentially increase one’s risk for breast cancer, and drinking too much is far worse for your heart than being a teetotaler. How do you find the sweet spot? Aim for no more than one drink a day if you’re a woman and two if you’re a man. And if you abstain during the workweek, you don’t have permission to binge drink over the weekend.

5. Cohabitate

While at first blush it may seem unlikely that a connection has been found between cohabitation and longevity, consider the following: when you live with someone else, you have a reason to pay more attention to your health and hygiene. You’ve got another person to hold you accountable for your actions and lifestyle habits. You’re less likely to engage in risky behaviors. And you’re more likely to have a built-in system for coping with stress, because another warm human body is present in your daily life.

If you come home mad, frustrated, and on the verge of a breakdown, you’ve at least got a sounding board. Which might explain why happy cohabitating couples repeatedly score better on blood pressure tests than their single counterparts. Whether or not this rule should entail marriage is up to you. And whether it should include children is another thing to consider.

6. Smile

Hint: Smiling will boost your mood no matter what. The act itself will trigger the release of pain-killing, brain-happy endorphins and serotonin. Besides, it’s easier to smile; it takes seventeen muscles to smile and forty-three to frown.

Maybe laugh a little, too.

7. Never skip breakfast

This old adage will never die. After fasting all night long, your body needs a metabolic jump-start to begin the day. We know that people who eat breakfast are just plain healthier in general and rarely have issues with weight (and if they do, the weight sloughs off once they start eating breakfast!). Skipping those morning calories to lose weight is one of the worst habits a person can develop. Front-loading your eating in the early part of the day will prevent you from overconsuming later, help you burn more calories, and allow you to get a wallop of nutrients when you need them.

Moreover, eating breakfast will give your brain a much-needed boost, fueling your productivity and creativity for the entire day. If you wait too long to eat after rising, stress hormones will start pumping and sabotage your body’s healthy metabolism. Too high a concentration of stress hormones like cortisol will encourage your body to retain fat, among other undesirable things.

From A SHORT GUIDE TO A LONG LIFE by David B. Agus, MD. Copyright © 2014 by Dr. David B. Agus. Excerpted with permission by Simon & Schuster, a Division of Simon & Schuster, Inc.