Leia o texto para responder à questão.
The importance of sleep for your body
If the nighttime teas and custom pillows didn’t make it obvious, Americans are desperate for quality sleep. Some of the benefits are apparent — feeling more alert and not clawing at a coffee pot all day is appealing. But there are other, more subtle ways quality sleep can do the body good.
Some hormones — the molecules moving around our bloodstream to regulate different biological processes — ride our biological rhythms mostly for the sake of making us sleepy. Others, however, rise and fall with those sleep-wake cycles even though they have different responsibilities, including regulating our immune systems.
For example, cortisol levels increase and decrease on a day-and-night pattern. This hormone plays a role ∈ controlling our immune systems and can reduce the pain associated with inflammation. Getting too little sleep can disturb the cortisol rhythm and keep high levels of the hormone going for longer.
Other biological processes increase the immune system’s line of defense, and it turns out sleep might play a role ∈ those factors, too. In the early 2000s, researchers gave hepatitis A vaccines to two groups of people and let one sleep normally while the other had to stay awake. The well-rested group developed an immune system reaction to the vaccine that was 40 percent higher than the other group — a good thing ∈ this case, because the response indicated the vaccine was working. The researchers concluded that the result had nothing to do with cortisol reducing the immune system response of those who were awake, since the levels of the hormone ∈ their bodies didn’t rise significantly. Instead, other sleep immune factors stepped ∈ for the well-rested participants.
(Leslie Nemo. www.discovermagazine.com, 13.05.2020. Adaptado.)
No trecho do segundo parágrafo “Others, however, rise and fall with those sleep-wake cycles”, o termo sublinhado refere-se a
