Lesson Plan: Impact of Climate Change on Circadian Rhythms and Sleep

Here is a step-by-step guide to using this lesson plan in the classroom/laboratory. We have suggested these steps as a possible plan of action. You may customize the lesson plan according to your preferences and requirements.

Step 1: Topic introduction and discussion (Go to the Video)

1. Use the video micro-lecture, ‘What Makes You Tick: Circadian Rhythms’ by Oxford Sparks, Oxford University, to introduce the topic of circadian rhythms.
2. Use this tool to explain why circadian rhythms are important for all livings beings.
3. Describe the role of photosensitive ganglion cells in the eye and the suprachiasmatic nucleus (SCN) in the hypothalamus of the brain, in managing the circadian rhythm.
4. Explain that maintenance of the circadian rhythm in individuals depends on environmental cues such as light and that any disruptions can be detrimental to their health.

Step 2: Extend Understanding (Go to the Reading)

1. Use this factsheet, ‘Circadian Rhythms’ by National Institute of General Medical Sciences (NIGMS) to further your students’ understanding of circadian rhythms. This tool is also available in Spanish.
2. Use the text to differentiate between circadian rhythms and biological clocks.
3. Define what is the master clock of the body and explain how it is responsible for keeping the circadian rhythm in sync with body physiology and behavior.
4. Explain that circadian rhythms are influenced by both natural (genetic) and environmental cues such as daylight and in turn are responsible for body function and health.
5. Use the text to explain how the body’s master clock is responsible for establishing sleep patterns in individuals.
6. Finally, discuss how disruptions in the circadian rhythm can lead to health problems.

Step 3: Discuss further (Go to the video and associated report)

1. Use the video and associated report, ‘Scientists warn of sleepless nights in a warming world’ by Ryan Cross, published in Science, to describe the effect of temperature on sleep cycles in individuals in the United States.
2. Use the tools to describe the findings of a study that reports that global warming and the accompanying higher nighttime temperatures have resulted in insufficient sleep and sleep disruptions in individuals in the United States.
3. Discuss the findings that the groups of poor and elderly individuals were more severely affected by this.
4. Further, discuss how the results of the study suggest that with the current and predicted rate of global warming, more sleep cycle disruptions could happen, leading to lowered productivity and health problems in a larger proportion of the population.

Step 4: Conduct the Classroom/Laboratory Activity

1. Use the set of activities, ‘Biological Rhythms’ by University of Washington, to enable students to explore their own biological rhythms in an engaging manner.
2. In the context of this lesson plan, direct your students to follow the instructions for ‘Experiment 1: The Ups and Downs of Body Temperature’ to investigate the body temperature rhythm.
3. Ask your students to do an additional activity from the ‘reaction time’ set of experiments for the same time-points.
4. Use the data collected to correlate the body temperature noted at specific time-points and the corresponding reaction times.
5. Use the correlation, if any, to discuss how warmer temperatures due to global warming could in turn affect body temperature related reaction times and therefore, biological rhythms in individuals.

Suggested questions/assignments for learning evaluation :

1. What are circadian rhythms? How are they related to sleep?
2. What are the factors involved in maintaining the circadian rhythm in living beings?
3. Why is the maintenance of circadian rhythms important for the health and well-being of individuals?
4. How is climate change affecting sleep and therefore the circadian rhythm in humans?

The tools in this lesson plan will enable students to:

1. explain what circadian rhythms in living beings are and what influences them
2. discuss the correlation of circadian rhythm and sleep cycles
3. describe the importance of sleep cycles for the health and well-being of individuals
4. explain how global warming could cause sleep deprivation and disruptions in humans

If you or your students would like to explore the topic further, these additional resources will be useful.