Life Time

Life Time

Your Body Clock and Its Essential Roles in Good Health and Sleep

Intriguing book! It explores what is known about how biological clocks are embedded in every aspect of human biology, guiding us toward the best times to sleep, eat, take medications, to think, and to work. Award-winning scientist, Russell Foster, explains how and why night-shift work, caring for a newborn, and too busy calendars take their tolls on mental and physical health. Excellent resource for counselors, clinicians, and business managers.

Foster empowers readers to refute old myths and get back into harmony with daily living and sleep. He covers scheduling meals to prevent obesity and diabetes; using exposure to light to get better sleep; and much more.


This book has the answers to everything you’ve ever wondered about your natural rhythms, from sleep to eating to exercise. Excellent, engaging and evidence-based, it’s a brilliant guide to an aspect of our health we don’t think about enough. – Claudia Hammond, author of The Art of Rest

This is an exemplary popular science book in many ways. It is readable. Full of surprising and useful facts…Unlike many science books with similar subtitles, it really might ‘revolutionize’ your life. – James McConnachie, Times (UK)

Life Time should certainly be mandatory reading for night-shift workers, but its messages are so universal that it would be hard not to gain some sleep smarts from its pages, whoever you are. – Alex Wilkins, New Scientist

Russell Foster, CBE, FRS, FMedSci
Course Expiration Date: Jun-16-2026
Course Performance Indicators: 1.1.1, 2.1.3, 4.1.2, 7.1.2, 8.2.3
Product Name

Book Only (2710)

Regular price $26.00 $26.00

21 CE Online Test Only (2711)

Regular price $134.00

21 CE Book & Online Test (2712)

Regular price $155.00

Book Details

Author Russell Foster, CBE, FRS, FMedSci
Year Published 2022
Edition 1st
Publisher Yale University Press
ISBN 978-0300266917
Format Hardback
Page Count 480
CDR Activity Numbers
  • 21 CE Online Test Only: 177328
  • 21 CE Book & Online Test: 177328

Course Objectives

Levels 1, 2, & 3 CPE

CPE Type: 740 Online/Web-based

Upon completion of this course, users will be able to:

1. Define REM and name three unique features of this type of sleep.

2. Discuss two functions of melatonin and name common drugs that reduce the body’s production of melatonin.

3. Describe what the circadian clock is and identify four of its most well-known functions that relate to health.

4. Name two unique interactions between light and circadian rhythms.

5. Explain two of cortisol’s functions, when it peaks, and two results of very high levels.

6. Describe the nutrition or health-related characteristics of the following: obstructive sleep apnea (OSA), delayed sleep phase disorder (DDSPD), narcolepsy, and sleep circadian rhythm disorders (SCRD).

7. Identify two associations between dementia and sleep disorders.

8. Name and discuss the key elements of cognition abilities and the expected highest time of day for most teenagers and adults, respectively.

9. Discuss why antihypertensive drugs and aspirin should be taken to be most

10. Describe two cases where it mattered the time of day when vaccinations were given.

11. Discuss the main functions of leptin and ghrelin, and how sleep deprivation
affects them.

12. Discuss when glucose intolerance is expected to be highest and explain why and its significance to meal planning.

Recommended For...

Registered Dietitian (RD/RDN)
Dietetics Technician Registered (DTR/NDTR)
Certified Diabetes Care & Education Specialists (CDCES)
Registered Nurse (RN)
Integrative & Functional Nutrition Academy Professional
American College of Sports Medicine

Why We Chose This Book

As new science explores the significance of how the circadian clocks in our bodies influence our quality of life, sleep quality, weight, and brain and physical health, we learn what disruption of our lives happens when we disrupt our clocks.

About the Author

Russell Foster, CBE, FRS, FMedSci, is professor of circadian neuroscience, Director of the Sir Jules Thorn Sleep and Circadian Neuroscience Institute, and head of the Nuffield Laboratory of Ophthalmology at the University of Oxford, UK. He has been working in the field of study for over 40 years.