I've just put together a few quotes I've found about the effects of fear/tension/pain. Some of these quotes were written for those experiencing back pain or chronic pain, but I feel they can apply to labor pain as well. I'm going to add my own experiences in another post.
"One of the first things that happens to all of us when we’re under stress is that we tense up—preparing to take action as part of the ancient fight-or-flight pathway in our body. When we can’t run or express our distress, and that distress is chronic, we tense even further. Interestingly, the words for emotional tension and muscle tension are the same. We feel tense emotionally and our muscles also tense up. And this is painful. Remember the last time you had a muscle cramp? You can’t move or think of anything else until that muscle relaxes. All manner of ordinary circumstances, such as fear of loneliness, financial failure, or having to deal with a difficult co-worker, child, or spouse can all result in muscle tension that we’re not even aware of. It’s not surprising that exactly the same class of drugs, the benzodiazepines (such as Valium and Ativan), can relax both muscles and anxiety. But these drugs don’t solve the problem; they merely mask it, and worse yet, they are highly addictive.
Chronic back pain results from stressful thoughts or emotions that aren’t released fully but instead are held in the form of chronic muscle tension. If you then believe that your back is damaged, you may begin to brace yourself, or begin assuming positions to guard against potential damage. This behavior and the beliefs that fuel it then trap you in a vicious cycle of pain and fear. The longer this goes on, the more it leads to psychological conditioning that deceives you into fearing physical activity. It has been found that fear of pain, especially in back pain sufferers, plays a very important role in the perception of pain. Frustration, anger, and depression further deepen the cycle."
"Injury and chronic pain contribute to muscle tension because muscles automatically contract around a painful site to support and protect the area.
Furthermore, if you adopt a guarded position to help protect yourself from pain, this will lead to further muscle contractions. A guarded position might mean walking with a limp or holding your neck in an awkward position. In this way, the muscle tension arises from a painful condition and then further contributes to pain. Furthermore, muscle tension can put pressure on nerves, leading to tingling and numbness."
"A MODEL OF PAIN-RELATED CYCLES
Much felt pain includes secondary pain resulting from pain-fear-tension cycles. Indirect actions that shift elements of the pain-fear-tension cycle or the related positive cycle are often able to decrease felt pain signals. By the time pained clients get to a bodyworker, it may be that most of the pain is secondary or that what started the cycle no longer exists
Primary pain or signal pain causes reflex holding, a splinting of injured or threatened parts by tight muscles, an early shift toward secondary pain cycles.
This double cycle summarizes the many ways we can lower or raise pain signals. Decreasing tension or fear can improve pain, just as tension and fear go down when pain stops. The linked positive cycle shows why gentle, pleasurable, rhythmic movement within your window of comfort not only leads to more effective body use, but can also decrease pain signals.
Physiologic background and assumptions:
In health, pain is a signal that something needs attention. Chronic pain also signals something needing attention, even when a response to stop the signal can't be found.
Secondary pain involves local muscle spasms, which limit circulation as tight muscles mash blood capillaries, cause waste products to accumulate, and produce pain signals. Holding against pain tightens muscles to create more tension, pain, and fear.
In the body, lower motor neurons (nerve cells) in the spinal cord extend out to the muscles and control contraction. Unless they are stroked and relaxed by signals from upper motor neurons in the brain, lower motor neurons fire all the time, causing muscle contraction, rigidity, and loss of control. In stroke, for example, loss of upper motor neurons results in rigidity and loss of relaxation ability in affected body parts. Tetanus produces rigidity because the nerve endings from upper centers are poisoned by tetanus toxin.
Increased sensory signals (like those from touch or gentle movement) give information about the body to the upper motor neurons of the functional mind. This sensory information lets these control centers automatically balance needed tension and release unneeded tension. Blocks to taking in sensory signals from the body are added pain, fear, tension, trying hard, tight goals, pressure, and thinking instead of feeling.
Positive assumptions are pain as signal, pain as message, pain as tool, pain as accepted (even if disliked). A negative assumption is pain as enemy. Even excessive, unwanted, unneeded pain, if assumed to be an enemy, is fought against and the rejection of hurting body parts creates disconnection and limits healing. Because body feedback is so important, signals not listened to will get stronger, not a response we want with pain signals."