Final answer:
True. Chronic stress adversely affects immune responses in healthy individuals, increasing susceptibility to infections like the common cold. Whereas short-term stress can boost the innate immune system, chronic stress leads to a suppressed immune function and higher susceptibility to illness.
Step-by-step explanation:
True. People under stress are indeed more vulnerable to infections. This vulnerability is particularly pronounced under conditions of chronic stress, which can inhibit immune responses in otherwise healthy individuals. Chronic stress has been demonstrated to suppress both innate and adaptive immune responses, making individuals more susceptible to various diseases. For instance, enduring stressors related to work or relationships over an extended period can increase the likelihood of contracting illnesses like the common cold.
Short-term stress, on the other hand, has been shown to enhance innate immune responses, which act quickly to protect the body. However, it simultaneously diverts resources away from the adaptive immune system. This trade-off could lead to problems fighting disease over time. Furthermore, psychoneuroimmunology is an emerging field studying the interaction between psychological processes and the nervous, endocrine, and immune systems.
It's important to note that older individuals or those with pre-existing conditions that weaken the immune system may still be more susceptible to illness even with short-term stress. The effects of stress on the immune system are complex and differ based on the duration and type of stressor.